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Two-step redox thermochemical cycles, capable of directly converting CO 2 and H 2 O respectively into CO and H 2 , offer a promising synthesis route towards green carbon-neutral fuels. The performance of such two-step cycles depends highly on the thermodynamic properties of splitting materials, particularly the solid-state enthalpy ( Δ h solid) and entropy (Δ s solid) changes during the reduction process. Here, we report an investigation into the roles of the Δ h solid and Δ s solid. We shall show that a high Δ s solid relaxes both reduction temperature and oxygen pressure, but increases oxidant consumption. Conversely, an increase in Δ h solid enhances reduction resistance while promotes oxidation reactions. There are therefore no perfect materials, and a trade-off is needed for an optimal solution. We also defined a thermodynamic region based on Δ h solid and Δ s solid and typical operating conditions, and showed that higher values of both Δ h solid and Δ s solid provided a larger reaction space. While lower Δ h solid and negative Δ s solid may be more suitable for isothermal cycles. Our analyses also suggest future efforts in searching for splitting materials with a high Δ s solid within an appropriate range of Δ h solid (280–460 kJ/mol). [Display omitted] • Trade-off caused by solid state enthalpy and entropy is a key issue. • High solid-state enthalpy and entropy are more suitable for temperature-swing cycle. • A thermodynamic region under typical operating conditions is defined. • Solid-state entropy of different candidate materials is discussed. [ABSTRACT FROM AUTHOR]

Methane pyrolysis is emerging as an attractive clean hydrogen production method. As its commercialization proceeds, the pyrolysis of natural gas (NG) becomes pertinent. In this work, the decomposition of pure methane and a realistic NG mixture are compared experimentally and numerically. Methane and NG pyrolysis are performed between 600 and 1200 °C over a fluidized bed of carbon particles heated by microwaves. Experimentally, no conclusive difference is observed in methane conversion between methane and NG pyrolysis. Numerically, the methane conversion rate is 8.5% higher for NG at 950 °C. The difference diminishes past 950 °C, becoming 0 past 1050 °C. The simulations showed that the enhanced methane decomposition in NG pyrolysis is due to an attack on methane by radicals generated during ethane and propane decomposition. The CO 2 in our NG mixture decomposes into CO. This work validates the longstanding use of methane pyrolysis as a surrogate for NG pyrolysis. • Experimentally, no conclusive difference between NG and pure CH 4 pyrolysis. • Numerically, NG pyrolysis had at most 8.5% higher methane conversion. • Radicals from ethane decomposition attacked methane and increased methane conversion. • Inlet C 2 H 6 > 10 vol% increased the outlet CH 4 rather than aiding its decomposition. • CO 2 in the NG mixture decomposed into CO, implying non-zero GHG emissions. [ABSTRACT FROM AUTHOR]

AlH 3 is a high-capacity hydrogen storage material but is prone to explosion. Thermodynamic and structural properties of AlH 3 -nanoparticles at different CO 2 inerting systems from ignition to combustion are studied using ReaxFF-MD method. The influence of CO 2 on AlH 3 -nanoparticles ignition and combustion is investigated by comparing the changes of surface O adsorption rates, particle charge, temperature rise rates and so on. Results indicate that an increase in CO 2 is crucial for suppressing AlH 3 -nanoparticles ignition and combustion by impeding the formation of an Al-rich environment. In contrast to three stages of AlH 3 -nanoparticles combustion in pure O 2 system: surface combustion, slow temperature rise, and self-sustaining combustion, the process of CO 2 inerting system is different, with third stage is slow temperature rise at a constant rate. When CO 2 concentration reaches to 90%, the dehydrogenation rate reduces by 70.0%, the temperature rise rate decreases by 78.6%, and the ignition delay time reaches 45 ps. [Display omitted] • The mechanism of CO 2 inhibition on ignition and combustion of AHNP is clarified. • The influence of CO 2 on AHNP dehydrogenation is also elucidated. • Revealing mechanisms at the atomic scale. [ABSTRACT FROM AUTHOR]

Given that SOF materials have both inorganic and organic properties and are easy to prepare and structurally designable, this paper carries out the microbehavioral analysis and membrane design of SOF-8, SOF-9, and SOF-10 membranes for the hydrogen purification process of RMFCs. Since three materials have complementary performance characteristics for hydrogen purification, this paper focuses on the gas separation behavior of these three composite membranes using molecular dynamics simulations. Results showed that the SOF-9a+10a composite membranes could 100% block CO 2 and CO, and displayed an excellent H 2 permeability of 6.118 × 105 GPU during H 2 /CO 2 separation, which exceeded the industry standard by nearly 105 times. Additionally, the SOF-9a+8 and SOF-10a+8 composite membranes improved gas selectivity and maintained high H 2 permeability. Moreover, microdiffusion analyses revealed that the small pore sizes and irregular-shaped pore channels effectively hindered CO 2 and CO transport. Microscopic analysis shows the potential of SOF composite membranes for gas separation. [Display omitted] • SOF composite membranes can effectively improve gas selectivity. • Small pore sizes and irregular pore channels can effectively block CO 2 transport. • SOF-9a+10 can 100% intercept CO 2 and CO. • The interaction between gas and membrane affects the gas separation performance. [ABSTRACT FROM AUTHOR]

The research has examined the effects of CO 2 dilution on ignition characteristics in H 2 /air mixtures. An ignition kernel was initiated by a laser-induced plasma in H 2 /air/CO 2 mixtures with a bulk velocity of 6.5 m/s. An infrared camera was used to measure radiation intensity emitted from H 2 O and ignition probabilities. A high-speed schlieren image system was utilized to measure ignition kernel areas and ignition time. High-speed chemiluminescence was performed to examine OH* intensities. Numerical simulations were conducted using GRI 3.0 mechanisms to calculate reaction rates and laminar flame speeds. The ignition probability is highest for the undiluted mixtures and decreases with increasing the CO 2 dilution fraction at constant adiabatic temperatures. A prolonged ignition time is observed at elevated CO 2 dilution concentrations. Increasing the CO 2 mole fraction decreases the ignition kernel growth, the integrated OH* intensity, and the integrated radiation intensity for each adiabatic temperature. CO 2 reacts with H radicals and decreases the production of OH*, OH, and H 2 O. The CO 2 dilution in the H 2 /air flames significantly contributes to the reduced reaction rate and flame speed, resulting in the low ignition probability. The high ignition probability is found at the large integrated OH* intensity in all cases. The ignition probability is high at the large integrated radiation intensity under the constant adiabatic flame temperatures. The OH* intensity is a critical parameter to estimate the ignition probability in the diluted lean hydrogen flames. • The effects of CO 2 dilution on the ignition process have been studied in lean premixed H 2 /Air flames. • The ignition probability decreases with increasing the CO 2 dilution fraction. • An increase in the CO 2 dilution fraction in the mixtures reduces OH* intensity and radiation intensity emitted from H 2 O. • The presence of CO 2 in the mixtures decreases reaction rates and flame speed. [ABSTRACT FROM AUTHOR]

For underground hydrogen storage (UHS), hydrogen (H 2) injection and withdrawal will create a temperature difference between the wellbore and the reservoir. The thermal diffusion driven by the temperature gradient (Soret effect) may enhance the mixing between H 2 and cushion gas and affects the purity of the produced H 2. In this work, the thermal diffusion process of H 2 and CO 2 under reservoir conditions is quantitatively observed for the first time. Results show that the Soret effect drives H 2 accumulation in the high-temperature region, and is influenced by temperature, pressure, and concentration. There is significant concentration difference between the high- and low-temperature sections when minor quantities of gas are injected. From experimental observations, we obtain the Soret coefficients across different physical conditions and propose a correlation for their prediction. Additionally, while thermal diffusion slows down in porous reservoirs, the concentration difference established along the temperature gradient remains unchanged at steady state. • The thermal diffusion process (Soret effect) between H 2 and CO 2 is measured. • The Soret effect drives H 2 accumulated in the high-temperature region. • The Soret effect depends on temperature, pressure and concentration. • With the increase of H 2 injection, the Soret effect is gradually weakened. • In porous reservoirs, the Soret effect is applicable but will slow down. [ABSTRACT FROM AUTHOR]

Using Ambient Pressure X-ray Photoelectron Spectroscopy (APXPS), this study investigates the reduction behavior of iron oxides in direct reduction (DRI) and blast furnace (BF) pellets. H 2 , CO, and a H 2 –CO mixture are used as reducing agents at 650 °C. The investigation aimed to elucidate variations in the rate of reduction over time and under different conditions. Additionally, contour plots are generated to visualize the X-ray photoelectron peak intensity variations as a function of time. Furthermore, phase stability diagrams based on Fe– O –C and Fe– O –H systems are employed to enhance the understanding of reduction behavior. Results revealed that an increased gas flow rate significantly accelerated the reduction rate due to enhanced gas diffusion, while elevated pressure facilitated the reduction of wüstite to metallic iron. Notably, the DRI pellet achieves around 90% metallization degree reduction with hydrogen, but the introduction of carbon monoxide into the reducing gas prevented the reduction of the DRI pellet. In the case of BF pellet reduction, approximately 20% metallization degree is observed using H 2 –CO (50:50), yet subsequent reoxidation of the reduced iron to wüstite and magnetite occurred. Further investigation identified a significant increase in the partial pressure of H 2 O and CO 2 , particularly within the surface porosities, as the underlying cause of this reoxidation phenomenon. • APXPS used to study iron oxide surface reduction in DRI and BF pellets. • Increased gas flow rate and pressure accelerated reduction rate. • DRI pellet achieved ∼90% metallization with H 2 , however, the value was ∼9% for BF. • BF pellet attained ∼20% metallization with H 2 –CO, while DRI showed no reduction. • Using CO–H 2 , reoxidation observed in BF due to a rise in H 2 O–CO 2 partial pressure. [ABSTRACT FROM AUTHOR]

A hierarchical structure alumina with high surface area was synthesized using a sol-gel method assisted by propylene oxide (PO), which was subsequently converted into alumina exhibiting different transitional phases (γ, δ, θ) through varying calcination temperatures. These aluminas were employed as substrates for the active copper phase in the RWGS catalyst, facilitating a systematic exploration of how the alumina phase influences catalyst performance. The characterized catalysts underwent assessments using techniques such as N 2 adsorption-desorption, XRD, H 2 -TPR, CO 2 -TPD, FESEM, and HRTEM. An examination of the impact of copper loading (ranging from 5.0 to 20.0 wt%) in the Cu/γ-Al 2 O 3 catalyst on RWGS performance revealed that the catalyst containing 15.0 wt% Cu exhibited the highest CO 2 conversion rate, achieving 8% at 300 °C under a 1CO 2 :1H 2 ratio at atmospheric pressure. This specific catalyst demonstrated 100% selectivity for CO. Evaluating the extended stability of Cu catalysts supported by γ-, δ-, and θ-Al 2 O 3 phases, all loaded with the same amount of Cu (15.0 wt%), was carried out at 450 °C. The δ- and θ-Al 2 O 3 -supported catalysts were able to maintain approximately 100% of their initial catalytic activities after 72 h, whereas the activity of the catalyst supported by γ-Al 2 O 3 decreased. The examination of the crystalline phases of the catalyst support and stability testing demonstrated the significant impact of porosity on mass transfer and the diffusion processes of reactants and production on the structure of the catalyst. This study revealed how adjusting the macropore size and porosity within various crystalline phases can optimize the filling degree and achieve an ideal balance between reaction and mass transfer rates. [Display omitted] • Catalyst support with the highest surface area was prepared via a sol-gel method. • Effect of hierarchical alumina as catalyst support was investigated in RWGS reaction. • 15 wt% Cu/γ-Al 2 O 3 catalyst exhibited the highest CO 2 conversion of 8% at 300 °C. • CO selectivity was 100% over 15 wt% Cu/γ-, δ-, and θ-Al 2 O 3 catalysts. [ABSTRACT FROM AUTHOR]

Chemical looping reforming of CH 4 coupled with CO 2 reduction stands out as a promising method for the syngas production. In this process, it is significant to design the oxygen carrier with high reactivity and stability. In this work, a highly efficient oxygen carrier is obtained by physically mixing Metal-modified ZSM-5 with LaFe 0.85 Ni 0.15 O 3 (LFN). The physical and chemical properties of the oxygen carriers are characterized by XRD, Raman, XPS, BET, TEM, NH 3 -TPD, CO 2 -TPD and CH 4 -TPD techniques. It is noted that mesoporous structures are formed over the Ni modified ZSM-5, due to that part of Ni elements replace Al in the silicaluminate framework. The structure change of the ZSM-5 promotes the gas adsorption capacity. CH 4 and CO 2 cannot be adsorbed on the surface of ZSM-5, while Ni-modified ZSM-5 enhances the adsorption capacity for CO 2 to a large degree. Moreover, Ni species are acted as active sites to facilitate the activation of CH 4 and CO 2 during the redox process. The aggregation-redispersion of Ni particles during the reduction-oxidation process inhibits the deactivation of Ni particles, which improves the stability of the oxygen carrier. Among all the obtained samples, LFN/10 wt% Ni-ZSM-5 exhibits the highest yields of syngas (8.38 mmol g−1) and CO (2.42 mmol g−1). [Display omitted] • Modifying ZSM-5 with Ni changed the pore structures and acid sites. • Ni-modified ZSM-5 promoted the adsorption capacity towards CO 2. • The activation of CH 4 and CO 2 could be improved over Ni-modified ZSM-5. • Ni particles maintained active by aggregation-redispersion under redox atmospheres. • LFN/10 wt% Ni-ZSM-5 exhibited high stability either in the activity or structure. [ABSTRACT FROM AUTHOR]

Defect engineering has been widely applied in the field of photocatalysis, and defects can be used to modify the surface structure and photoelectric properties of catalysts so as to achieve the purpose of regulating the activity and stability of catalysts. However, design of a highly efficient photocatalyst with abundant defects remains a challenging task in current research. Therefore, in this study, graphitic carbon nitride (g-C 3 N 4) with abundant three-coordinated nitrogen (N 3C) vacancies and pore structures was obtained using a facile hydrothermal method with the assistance of glycerol. Under visible light (λ > 420 nm) irradiation, the 50CN (volume ratio of glycerol/water is 50/10) catalyst exhibits a superior CO release rate (4.18 μmol g−1 h−1), which is 12.06 times higher than the reference GCN (0.32 μmol g−1 h−1), and the corresponding apparent quantum yields (AQY) of 50CN is 0.24 %, which is significantly higher than that of GCN (0.045 %). Successful introduction of N 3C vacancies is conducive to broaden light response range of the catalyst, enhancing the separation and migration efficiency of photogenerated charges, and providing more adsorption active sites to promote the adsorption and activation of CO 2 molecules, thus effectively boosting photocatalytic CO 2 reduction activity. In addition, the N 3C vacancies can effectively lower the CO 2 activation energy barrier and reduce the energy consumption required for the reaction. This work offers valuable new insights into defect engineering in g-C 3 N 4 for the development of high-performance photocatalysts for CO 2 reduction. [ABSTRACT FROM AUTHOR]

The sulfur over calcium ratio (S/Ca) in foraminiferal shells was recently proposed as a new and independent proxy for reconstructing marine inorganic carbon chemistry. This new approach assumes that sulfur is incorporated into CaCO 3 predominantly in the form of sulfate (SO 4 2−) through lattice substitution for carbonate ions (CO 3 2–), and that S/Ca thus reflects seawater [CO 3 2–]. Although foraminiferal growth experiments validated this approach, field studies showed controversial results suggesting that the potential impact of [CO 3 2–] may be overwritten by one or more parameters. Hence, to better understand the inorganic processes involved, we here investigate S/Ca values in inorganically precipitated CaCO 3 (S/Ca (cc)) grown in solutions of CaCl 2 − Na 2 CO 3 − Na 2 SO 4 − B(OH) 3 − MgCl 2. Experimental results indicate the dependence of sulfate partitioning in CaCO 3 on the carbon chemistry via changing pH and suggest that faster precipitation rates increase the partition coefficient for sulfur. The S/Ca ratios of our inorganic calcite samples show positive correlation with modelled [CaSO 4 0] (aq) , but not with the concentration of free SO 4 2− ions. This challenges the traditional model for sulfate incorporation in calcite and implies that the uptake of sulfate potentially occurs via ion-ion pairs rather than being incorporated as single anions. Based on the [Ca2+] dependence via speciation, we here suggest a critical evaluation of this potential proxy. As sulfate complexation seems to control sulfate uptake in inorganic calcite, application as a proxy using foraminiferal calcite may be limited to periods for which seawater chemistry is well-constrained. As foraminiferal calcite growth is modulated by inward Ca2+ flow to the site of calcification coupled to outward H+ pumping, sulfate incorporation as CaSO 4 0 ion-pair in the foraminifer's shell also provides a mechanistic link for the observed relationship between S/Ca (cc) and [CO 3 2–]. [ABSTRACT FROM AUTHOR]

Abiotic synthesis of CH 4 in seafloor hydrothermal fluids is generally assumed to occur via heterogeneous reactions on mineral surfaces. Stepwise homogeneous reduction of CO 2 has, however, been suggested as an alternative (but sluggish) abiotic pathway to CH 4 , potentially via metastable species of intermediate oxidation states. In this study, we examine the effect of two temperature-dependent methylated species − methanol (CH 3 OH) and methanethiol (CH 3 SH), on homogeneous CH 4 formation rates under long-term simulated hydrothermal conditions. Aqueous solutions containing formic acid (H13COOH, generating 13CO 2 and H 2) were heated with and without H 2 S at 300–325 °C (35 MPa) in a flexible Au reaction cell over several years without added minerals. Substantial 13C-labeled CH 4 and CH 3 OH production from 13CO 2 was observed over 4.3 yr, with aqueous CH 4 formation varying with CH 3 OH abundance – a strong function of dissolved H 2 abundance and, inversely, temperature. CH 4 production was slower at 325 °C with lower CH 3 OH concentrations (in equilibrium with CO 2 and H 2), and faster at 300 °C, accompanying an equilibrium-controlled increase in CH 3 OH. Fastest CH 4 production occurred at 300 °C following injection of H 2 S and H13COOH, which led to rapid formation (<4 days) of 13C-labeled CH 3 SH that subsequently decomposed over a further 0.8 yr, partly to 13CH 4. Heating aqueous 13CH 4 to 345–387 °C (33–35 MPa) in the presence of an oxidizing hematite-magnetite-pyrite assemblage, however, yielded no detectable CH 3 SH after 112 days indicating the reverse reaction is inhibited under favorable thermodynamics. Neither direct reduction of CO 2 to CH 3 SH nor CO 2 -CH 3 SH equilibrium were evident at 300 °C, implying CH 3 SH and CH 3 OH play disparate roles in homogeneous carbon reduction to CH 4. Longer chain hydrocarbons (C 2+ alkanes) remained low throughout the experiments. CH 3 SH abundances previously reported in vent fluids at the Von Damm hydrothermal field correlate strongly with demonstrably abiotic HCOOH there, suggesting the reduction of HCOOH to CH 3 SH observed in this study may also occur in vent fluids. A comparison of mineral-free 13CH 4 production rates reported here with 13CO 2 reduction experiments involving minerals indicates that homogeneous reduction proceeds at similar rates to purported transition metal-catalyzed 13CH 4 production, and is generally faster than experiments with either added olivine or ultramafic rock. Previous claims of substantial mineral-catalyzed abiogenic CH 4 production are therefore not supported by our study. Homogeneous CO 2 reduction may be a significant source of methylated compounds and CH 4 in hydrothermal fluids characterized by decadal (or longer) residence times, such as those found in mineral-hosted inclusions or occluded fractures in igneous basement, requiring only moderate temperatures and abundant H 2 to proceed. [ABSTRACT FROM AUTHOR]

• CaCl 2 is an additive suitable for pyrometallurgical recovery of spent LIBs. • CaCl 2 has good chlorination ability and slag optimization ability. • SiO 2 and CO 2 in the system contribute to the increase in HCl yield. The difficulty of separating Li during pyrometallurgical smelting of spent lithium-ion batteries (LIBs) has limited the development of pyrometallurgical processes. Chlorination enables the conversion of Li from spent LIBs to the gas phase during the smelting process. In this paper, the effects of four solid chlorinating agents (KCl, NaCl, CaCl 2 and MgCl 2) on Li volatilization and metal (Co, Cu, Ni and Fe) recovery were investigated. The four solid chlorinating agents were systematically compared in terms of the direct chlorination capacities, indirect chlorination capacities, alloy physical losses and chemical losses in the slag. CaCl 2 was better suited for use as a solid chlorinating agent to promote Li volatilization due to its excellent results in these indexes. The temperature required for the release of HCl from MgCl 2 , facilitated by CO 2 and SiO 2 , was lower than 500 °C. The prematurely released HCl failed to participate in the chlorination reaction. This resulted in approximately 12 % less Li volatilization when MgCl 2 was used as a chlorinating agent compared to when CaCl 2 was used. In addition, the use of KCl as a chlorinating agent decreased the chemical dissolution loss of alloys in the slag. The performance of NaCl was mediocre. Finally, based on evaluations of the four indexes, recommendations for the selection and optimization of solid chlorinating agents were provided. [ABSTRACT FROM AUTHOR]

[Display omitted] The Sudokwon landfill (SL) in the Seoul metropolitan area, South Korea, is among the world's largest landfills, striving to curtail landfill gas (LFG) emissions and achieve carbon neutrality by 2050. Since 2005, the SL Management Corporation (SLC) has measured LFG emissions (i.e., methane (CH 4) and carbon dioxide (CO 2)) using a dynamic flux chamber proposed by the US EPA. However, uncertainty prevails in validating the reduction of LFG emissions due to the limited spatiotemporal data coverage. In 2020, an eddy covariance (EC) system was installed to enhance measurements, revealing highly fluctuating LFG emissions driven by waste layer LFG production, LFG collection, and atmospheric pressure changes. During the study period, the annual CH 4 emission increased slightly from 465.0 ± 4.2 to 485.5 ± 6.4 g C m−2, while that of CO 2 decreased by 2/3 (from 408.7 ± 16.5 to 270.6 ± 18.8 g C m−2), primarily due to the doubled CO 2 uptake by the vegetated topsoil. Our first long-term (March 2020 to February 2022) quasi-continuous monitoring using EC (with a gap-filling and partitioning technique based on Random Forest) emphasizes the difficulty of temporal upscaling of discontinuously observed surface emissions to quantify the LFG inventory and the need for continuous observations or suitable proxies (e.g., atmospheric CH 4 concentration). [ABSTRACT FROM AUTHOR]

Porous graphene structures continue to attract attention with their increasingly superior properties. Especially through carbon-based porous structures in a framework form have found applications in various fields such as gas storage. In this study, graphene fragments were utilized as pillars between graphene layers to create a novel framework structure, and geometry optimization was performed under different external pressures. Adsorptions of hydrogen, carbon dioxide, and methane gases, which need to be controlled for combating global warming, were investigated for the optimized structure. It is found that the structure which withstand deformations up to 5 GPa of external pressure could store 2.005 wt % hydrogen hydrogen at room temperature and 100 bar pressure. Moreover, capable to adsorb 6.426 and 8.776 mmol/g carbon dioxide and methane at room temperature and 1 bar pressure, respectively. In conclusion, alongside other potential applications like electrical and energy storage, its usability as a gas adsorbent for combating global warming have a great potential. • Graphene pillared porous graphene framework structure constructed. • Structure optimized under various external pressures. • The structure withstand up to 6 GPa selected for gas adsorption. • Hydrogen, Carbon dioxide and Methane stored inside. [ABSTRACT FROM AUTHOR]

Dry reforming of methane (DRM) enables the conversion of two greenhouse gases, CH 4 and CO 2 , into syngas, offering remarkable environmental and economic benefits. The primary challenge in this process lies in maintaining the catalyst's high catalytic activity and stability. In this study, natural vermiculite (VMT) was employed to modify the layer carrier with a large specific surface area and suitable pore size. By combining the structural characteristics of perovskite, we synthesized the LaNiO 3 /VMT-SiO 2 perovskite catalyst using the citric acid complex method for methane dry reforming reaction. The results demonstrate that at T = 750 °C and GHSV = 36,000 mL/(h·g cat), the catalyst exhibits excellent activity (achieving maximum conversions of 82% for CO 2 and 90% for CH 4) as well as stability (up to 24 h). Characterization techniques such as XRD and TEM revealed that the catalyst possesses exceptional catalytic activity and stability due to its horizontally distributed active component Ni within perovskite. Through pretreatment, we obtained an active component Ni with small particle size and uniform dispersion along with a carrier featuring a large specific surface area. Furthermore, alkaline La 2 O 3 in the reduced catalyst enhances its carbon resistance. • Using Xinjiang vermiculite to prepare a support with mesoporous layered structure for methane and carbon dioxide reaction. • Prepare perovskite type catalysts using citric acid complexation method, and load them on vermiculite-based supports to obtain highly dispersed catalysts. • The reduced catalyst contains lanthanum oxides and hydroxides, increasing the alkaline sites of the catalyst and facilitating the elimination of carbon dioxide and carbon deposition. [ABSTRACT FROM AUTHOR]

This study introduces a novel method for hydrogen fuel generation using ultrasound technology through the disassociation of water into hydrogen and oxygen. The proposed experimental setup comprises several key components: a power supply, an ultrasonic generator, two transducers, a reactor vessel, two vapor traps, a condenser, a valve, a hydrogen storage, a humidity sensor and a hydrogen measurement sensor. The system operates at a power of 100 W and a frequency of 40 kHz, and the reactor vessel contains 2L of solution. The study results show a variability in hydrogen production rates under different experimental conditions. The distilled water used in the experiments at 25 °C produces hydrogen at a rate of 0.05 μmol/min, which increases to 0.066 μmol/min at 70 °C. The tap water gives hydrogen production rates ranging from 0.044 μmol/min at 25 °C to 0.06 μmol/min at 70 °C. The lake water produces hydrogen at rates between 0.036 μmol/min and 0.054 μmol/min, while the wastewater ranges from 0.028 μmol/min to 0.044 μmol/min. The present study investigates the effect of CO 2 injection into the sonoreactor on the system performance and shows that hydrogen production rates increase over a 20-min period for the water resources, with higher CO 2 flow rates leading to improved production rates. These findings demonstrate the potential of ultrasound technology for eco-friendly hydrogen production, marking a promising alternative to conventional methods and contributing valuable insights to the field of sustainable energy. [Display omitted] • The study investigates an innovative sonic method of hydrogen generation. • The present system is proposed for clean hydrogen generation. • The experiments are conducted at a frequency of 40 kHz and power of 100 ± 10 W. • The hydrogen generation is tested under various water sources at different temperatures. • The hydrogen generation is assessed by injecting CO 2 into the sonoreactor solution. [ABSTRACT FROM AUTHOR]

A reverse flow porous medium reactor with premixed and non-premixed flames was experimentally investigated to evaluate the influence of steam and carbon dioxide on methane (CH 4) filtration combustion for syngas production. Premixed, non-premixed, and non-premixed with steam were the tested cases for different injection configurations. Thermal profiles, combustion products, hydrogen (H 2) and carbon monoxide (CO) yields for several equivalence ratios are analyzed. Non-premixed case exposed higher maximum temperatures due to the reactant accumulation at the crosswise injection position, with a temperature of 1615 K. The lack of homogenization of the reactants in this configuration leads to low H 2 and high CO concentrations compared to the premixed case. The maximum CO yield was 92.81% for the non-premixed configuration with alternated air injection, while the maximum H 2 yield was 37.8% for the premixed air-methane-steam case. It was found that the air-methane-carbon dioxide mixtures had lower temperatures, combustion wave velocities, and H 2 and CO concentrations, compared to the air-methane, and air-methane-steam mixtures, but higher CH 4 and CO 2 concentrations. The premixed configuration with air-methane-carbon dioxide mixture showed higher temperatures, and H 2 and CO concentrations, compared to the non-premixed configuration. Further studies are necessary to optimize the operation of these types of reactors. • Methane filtration combustion in a reversal flow porous media reactor. • Steam and carbon dioxide on the methane filtration combustion were investigated. • Thermal profiles, and hydrogen and carbon monoxide production were analyzed. • Premixed flames showed higher H 2 and CO production than non-premixed flames. [ABSTRACT FROM AUTHOR]

Developing efficient photocatalysts with low cost, high performance, and high selectivity is essential and imperative for CO 2 conversion and utilization, yet it remains a big challenge. Herein, a novel Ce-doped TiO 2 aerogel with oxygen vacancy anchored on the oriented carbonaceous (Ce–TiO 2 @CS) is synthesized by the sol-gel technique, combined with the freeze casting, supercritical drying technique, and heat treatment processes. The Ce–TiO 2 @CS aerogel has a typical aerogel-like structure, with the Ce–TiO 2 aerogel anchored on the oriented porous carbon, rendering a large BET-specific surface area of 124 m2/g, which leads to enhanced photocatalytic activity. The Ce-doping into the pristine TiO 2 results in impurity levels within the band gap, which extends the light response range to the visible light region. In addition, the rapid combination of electrons and holes is prevented via the two-phase microstructures and rapid transfer rate of electrons within the oriented porous carbon. The yields of CH 4 and CO are as high as 9.45 μmol h−1 g−1 and 42.26 μmol h−1 g−1, respectively, which are 28.6 and 2.46 times higher than those of pristine TiO 2 aerogel under simulated solar spectrum conditions without any sacrificial agents or co-catalysts, The density functional theory (DFT) calculation shows that larger C–O bonds of CO 2 molecule and more negative adsorption energy have occurred on the Ce–TiO 2 @CS aerogel, indicating that the CO 2 activation has been enhanced, which greatly improves the CO 2 photoreduction activity. This work may guide the designing of aerogel-based photocatalysts for CO 2 photocatalytic reduction. [ABSTRACT FROM AUTHOR]

The development of multi-functional and highly mixed ionic-electronic conductive perovskite oxide-based electrodes is becoming an established trend for designing and developing SOFC/SOEC reversible cells. Ideally, the same material can be employed at both electrodes provided that structural stability, high conductivity and catalytic activity are preserved in different operational atmospheres. Here, controlled Fe substitution with a small extent (0.5 mol%) of platinum at the B-site of a lanthanum strontium ferrite is proposed as an effective method to enhance the original oxide properties as both air and fuel electrode for solid oxide cells. The effects of low Pt-doping on La 0.6 Sr 0.4 FeO 3-δ structure, morphology and electrocatalytic activity are investigated and discussed. La 0.6 Sr 0.4 Fe 0.995 Pt 0.005 O 3-δ (05P-LSF) is first tested as air electrode, displaying lower area specific resistance as compared to the Pt-free perovskite. 05P-LSF structural stability and conductivity are assessed in 100 % CO 2 and 50 % CO 2 –50 % CO environments. Symmetric devices are then tested as SOECs in 100 % CO 2 , obtaining a current density output of 1.08 A/cm2 at 1.5 V. Electrochemical impedance spectroscopy (EIS) with distribution of relaxation times analysis (DRT) are used to provide insights on the electrode operation. Pt nanoparticle exsolution at the fuel electrode is induced by voltage application. The device stability under applied voltage is assessed for over 120 h. SOFC/SOEC characterization in a 50 % CO 2 /50 % CO mixture at 850 °C is also provided, obtaining a maximum power density of 270 mW/cm2 in SOFC mode, and a current density of 0.91 A/cm2 at 1.5 V in SOEC mode. [ABSTRACT FROM AUTHOR]

The combination of microbial CO 2 reduction process and photocatalysis can meet the economic goal of sustainable carbon neutrality. Solar-energy as driven force can be achieved, by mimicking natural photosynthesis through the interaction between photo-responsive semiconductor nano-materials and electroautotrophic bacteria (EAB). Therefore, we reviewed the engineering strategies developed in recent years for photocatalytic microbial fixation of CO 2 to improve extracellular electron transfer (EET) rate and enhance the conversion efficiency of solar-to-chemical energy, including (1) the application principles of semiconductor nanomaterials in microbial CO 2 reduction systems; (2) photocathode; (3) photoanode; (4) dual photoelectrodes and (5) inorganic-microbe hybrid system; (6) perspectives on future challenges and opportunities for photocatalytic microbial fixation of CO 2 for sustainable energy and chemical production. This review will provide a theoretical basis for the future development of photocatalytic microbial fixation of CO 2 in energy harvesting, CO 2 fixation, and chemical synthesis. [ABSTRACT FROM AUTHOR]

Constructing the interface of Ni/Y 2 O 3 heterogeneous catalyst is a feasible strategy for efficient catalyst design in CO 2 methanation, which can create the active Y–O–Ni interfacial sites by utilizing the interaction between Ni and Y 2 O 3. In this work, the strategy of using different nickel precursors (nickel nitrate, nickel acetate, basic nickel carbonate and nickel citrate) was used to prepare various Ni-based catalysts supported on Y 2 O 3 , which were estimated for their catalytic performance on CO 2 methanation. The catalysts were characterized based on BET, XRD, TEM, H 2 -TPR, XPS and CO 2 -TPD, etc. The results indicated a close correlation between the metal dispersion and particle size of Ni/Y 2 O 3 catalysts and the nickel precursor employed. The Y–O–Ni interface structure in Ni/Y 2 O 3 catalysts, associated with basic sites, provides a richer source of basic sites, offering more active sites for CO 2 adsorption and activation. Ni/Y 2 O 3 catalyst prepared with nickel nitrate as the precursor exhibited characteristics such as a highly enhanced nickel dispersion, a smaller nickel particle size, and more abundant metallic Ni0 sites. Moreover, nickel nitrate-derived Ni/Y 2 O 3 catalyst exhibited optimal catalytic activity, achieving a CO 2 conversion rate of up to 92 % at 300 °C, with 100 % selectivity to CH 4 , and displaying good stability over 30 h. Therefore, the dispersion of Ni and the size of Ni particles could be controlled by adjusting the precursor, which is closely associated with the catalytic activity of Ni/Y 2 O 3 catalyst. This work unveils the interface-property relationship of Ni/Y 2 O 3 catalysts and provides a new insight into strategy of constructing more effective Ni-based catalyst for CO 2 methanation through the controlled nickel precursor. [Display omitted] • The catalytic performance and properties of Ni/Y 2 O 3 is influenced by the Ni precursor in CO 2 methanation. • Ni–N exhibits superior activity at 300 °C achieving a CO 2 conversion of 92 % at 300 °C, with 100 % selectivity to CH 4. • The nickel precursor influences the particle size of Ni and the metal-support interaction. • The Y–O–Ni interface structure in Ni/Y 2 O 3 is associated with basic and metallic Ni sites. [ABSTRACT FROM AUTHOR]

This study experimentally investigated the influence of gasoline injection pressure (GIP) on the performance and hydrogen knock limit of a gasoline direct-injection hydrogen–gasoline dual-fuel engine. The GIP was varied from 50 to 140 bar, and hydrogen was introduced at a step size of 2 LPM until knock onset at spark timings of 4° and 12° CA before top dead center (BTDC). The hydrogen knock limit was extended at a higher GIP, with maximum hydrogen flow rates of 10 and 16 LPM at 12° CA and 4° CA BTDC, respectively. Increasing the GIP and retarding the spark timing negatively affected brake thermal efficiency, brake mean effective pressure, and in-cylinder pressure. The CO 2 and NO x emissions decreased, and the CO emissions increased with an increase in the GIP. The cyclic variation increased considerably with GIP. However, hydrogen blending exhibited a completely opposite trend to that of GIP. • Study of the effect of gasoline injection pressure in a hydrogen-gasoline dual fuel engine. • The hydrogen knock limit was influenced by the variation in gasoline injection pressure. • Increasing the gasoline injection pressure showed a negative effect on the performance and combustion characteristics. • Cyclic variation increased at higher gasoline injection pressure and reduced with hydrogen blending. • Increased hydrogen flow rate was observed at higher gasoline injection pressure and retarded spark timing. [ABSTRACT FROM AUTHOR]

Reducing CO 2 by CH 4 (CRM) is of great significance for alleviating greenhouse effects and fuel shortages. However, the high energy consumption and low yield of fuel, as well as the deactivation of Ni based catalysts constrained its development. Herein, a novel Ni–CeO 2 /Al 2 O 3 catalyst for photothermal catalytic CRM merely upon focused light irradiation was reported. Very high yield of H 2 and CO (80.2 and 96.3 mmol min−1 g−1) and excellent catalytic durability were achieved. The results of UV-VIS-IR diffuse reflectance spectra and experimental test indicate that high yield of H 2 and CO originates from efficient photothermal conversion and the molecular activation effect of light. More importantly, Ni–CeO 2 /Al 2 O 3 exhibits better carbon deposition resistance than Ni/Al 2 O 3. The structural characterization and experimental evidences reveal that the active lattice oxygen in CeO 2 nanoparticles can be transferred to Ni nanoparticles via Ni–CeO 2 interface to accelerate carbon oxidation and form oxygen vacancies. The formed oxygen vacancies can re-adsorb and activate CO 2 to form new active lattice oxygen. [Display omitted] • Dual nanoparticles catalyst with rich Ni–CeO 2 interface was synthesized. • High production rate of H 2 and CO were achieved for photothermal catalytic merely upon focused light irradiation. • Molecular activation effect of light enhanced production rate of H 2 and CO. • Rich Ni–CeO 2 interface enhanced the carbon deposition resistance. [ABSTRACT FROM AUTHOR]

This study comprehensively investigates H 2 loss resulting from injecting two gas mixtures: I (60% H 2 + 30% CH 4 + 5% N 2 + 5% CO 2) and II (60% H 2 + 30% N 2 + 5% CH 4 + 5% CO 2) into an aqueous solution containing 20,000 ppm sodium chloride and 100 ppm acetic acid (a microbial by-product of acetogenesis) within Bandera clay-rich sandstone reservoirs. Conducted at 42 °C and 1350 psi, various analytical techniques, including X-ray diffraction (XRD), Scanning Electron Microscopy with Energy Dispersive X-ray (SEM-EDX) spectroscopy, Fourier Transform Infrared (FTIR) spectroscopy, porosity and permeability assessments, pH and ion analysis, and gas chromatography, were utilized to assess the relevant properties of rocks, formation water, and gas content before and after 50 days treatment. The results indicate minimal sample reactivity, with dissolution primarily affecting dolomite and albite minerals. On average, porosity increased by 19% in formulation I and 15% in formulation II, while permeability decreased by 4.7% in formulation I and 5.3% in formulation II. In formulation I, H 2 fraction decreased by 2.79%, CH 4 increased by 7.15%, and CO 2 decreased by 9.36%, with N 2 remaining constant, whereas in formulation II, H 2 only decreased by 1.3%, CH 4 increased by 19.22%, and CO 2 decreased by 3.58%, with N 2 remaining consistent. Overall, the N 2 cushion gas condition (i.e., formulation II) slightly outperformed CH 4 in minimizing H 2 losses. This study thus provides significant insights into potential H 2 loss within a microbial-by-product-rich environment for underground hydrogen storage. • Comparative study on H 2 losses using CH 4 or N 2 cushion gas via microbial-byproduct is reported. • Biogeochemical reactions (dissolution/precipitation) induced by the mixtures are very weak. • The presence of acetic acid increased pH from 3.17 to 6.23 and 6.63 for CH 4 and N 2 cushion. • CH 4 cushion resulted in 2.79% H 2 loss compared to N 2 cushion gas (1.3% loss) based on gas chromatography. • Findings provide valuable insights into potential H 2 loss within a microbial rich environment. [ABSTRACT FROM AUTHOR]

The co-pyrolysis of torrefied oiltea camellia shells (OCS) and reused polypropylene (PP) was investigated for pyrolysis oil, pyrolysis gas and carbon nanotubes (CNTs) distribution characters in a two-stage pyrolysis system. Compared with raw OCS/PP, the quality of pyrolysis oil from torrefied OCS and PP was upgraded while yield decreased gradually. In particular, torrefaction pretreatment was beneficial to the formation of aromatic hydrocarbons and the higher selectivity of phenols in pyrolysis oil. And serious N 2 torrefaction (260 N) and slight CO 2 torrefaction (200C) is more conducive to the synthesis of C6–C11 (gasoline component). In addition, torrefaction could contribute to lower volatiles, which resulted in a lower yield of CNTs. For comparison, higher graphitized CNTs was prepared from the co-pyrolysis of torrefied OCS and PP. Appropriate torrefaction temperature and atmosphere have a potential for high value conversion of pyrolysis oil, pyrolysis gas and CNTs from co-pyrolysis of biomass and plastics. [Display omitted] • Aromatic hydrocarbons and phenols were the main content obtained by torrefaction. • CO 2 torrefaction exhibited higher gas and lower bio-oil yield than N 2 torrefaction. • Production of liquid oil, CNTs and gas from torrefied biomass and plastics. • Strategies to facilitate biomass high value on products conversion were provided. [ABSTRACT FROM AUTHOR]

MXenes exhibit unique structural flexibility, excellent carrier mobility and abundant active sites, making them valuable catalysts in photocatalysis. The electronic properties and photocatalytic activity of Janus ZrMCO 2 (M = Ti, Hf) MXenes are investigated by hybrid HSE06 functional. Photocatalytic activities of hydrogen evolution reaction (HER) and oxygen evolution reaction (OER) are further explored. Structural stability is proved by negative cohesive energy and elastic stiffness coefficients. ZrTiCO 2 and ZrHfCO 2 are all direct semiconductors. Ti/Hf doping makes conduction band minimum (CBM) have a redshift and induces the reduction of band gaps of Janus systems. The three systems are potential photocatalysts due to their appropriate bandgaps and significant absorption in visible region. The irradiation-generated holes and electrons can easily drive the HER or OER on ZrHfCO 2 MXene due to the small overpotential. ZrHfCO 2 and Zr 2 CO 2 are highly efficient for photocatalytic hydrogen production with STH efficient of 30.3%. Hf doping improves the photocatalytic reduction of CO 2 , while The Ti/Hf doping doesn't improve the N 2 reduction. • Ti/Hf doping induces the reduction of band gaps of Janus systems. • ZrHfCO 2 and Zr 2 CO 2 are highly efficient for photocatalytic hydrogen production with STH efficient of 30.3%. • ZrHfCO 2 and Zr 2 CO 2 can perform complete PWS reactions in acidic solution. • Hf doping can reduce the overpotential for OER and HER of Zr 2 CO 2. [ABSTRACT FROM AUTHOR]

• The stronger electronegativity of Ag in Ag/Co 3 O 4 led to richer surface Co3+. • Ag/Co 3 O 4 gained by Ag-reduction method showed higher surface Co3+/Co2+ ratio. • The reducibility of Co 3 O 4 was greatly improved by the loading of Ag via reduction method. • Ag/Co 3 O 4 prepared by Ag-reduction method showed higher catalytic activity. Silver (9 wt.%) was loaded on Co 3 O 4 -nanofiber using reduction and impregnation methods, respectively. Due to the stronger electronegativity of silver, the ratios of surface Co3+/Co2+ on Ag/Co 3 O 4 were higher than on Co 3 O 4 , which further led to more adsorbed oxygen species as a result of the charge compensation. Moreover, the introducing of silver also obviously improved the reducibility of Co 3 O 4. Hence the Ag/Co 3 O 4 showed better catalytic performance than Co 3 O 4 in benzene oxidation. Compared with the Ag/Co 3 O 4 synthesized via impregnation method, the one prepared using reduction method (named as AgCo-R) exhibited higher contents of surface Co3+ and adsorbed oxygen species, stronger reducibility, as well as more active surface lattice oxygen species. Consequently, AgCo-R showed lowest T 90 value of 183°C, admirable catalytic stability, largest normalized reaction rate of 1.36 × 10−4 mol/(h·m2) (150°C), and lowest apparent activation energy (E a) of 63.2 kJ/mol. The analyzing of in-situ DRIFTS indicated benzene molecules were successively oxidized to phenol, o-benzoquinone, small molecular intermediates, and finally to CO 2 and water on the surface of AgCo-R. At last, potential reaction pathways including five detailed steps were proposed. [ABSTRACT FROM AUTHOR]

• Succinic acid production of 30 g/L was shown with 6 gC/L MgCO3 and 24 gC/L glucose. • The inorganic carbon of "carbonate:CO2 = 1:9″ presented the highest CO2 fixation. • The PEPCK/LDH was enhanced at high gaseous CO2, by promoting succinic acid path. • 50%−65% of inorganic carbon utilization was increased via stepwise CO2 addition. • 20%−30% increment in succinic acid selectivity was shown via stepwise CO2 addition. Utilizing CO 2 for bio-succinic acid production is an attractive approach to achieve carbon capture and recycling (CCR) with simultaneous production of a useful platform chemical. Actinobacillus succinogenes and Basfia succiniciproducens were selected and investigated as microbial catalysts. Firstly, the type and concentration of inorganic carbon concentration and glucose concentration were evaluated. 6 g C/L MgCO 3 and 24 g C/L glucose were found to be the optimal basic operational conditions, with succinic acid production and carbon yield of over 30 g/L and over 40%, respectively. Then, for maximum gaseous CO 2 fixation, carbonate was replaced with CO 2 at different ratios. The "less carbonate more CO 2 " condition of the inorganic carbon source was set as carbonate: CO 2 = 1:9 (based on the mass of carbon). This condition presented the highest availability of CO 2 by well-balanced chemical reaction equilibrium and phase equilibrium, showing the best performance with regarding CO 2 fixation (about 15 mg C/(L·hr)), with suppressed lactic acid accumulation. According to key enzymes analysis, the ratio of phosphoenolpyruvate carboxykinase to lactic dehydrogenase was enhanced at high ratios of gaseous CO 2 , which could promote glucose conversion through the succinic acid path. To further increase gaseous CO 2 fixation and succinic acid production and selectivity, stepwise CO 2 addition was evaluated. 50%-65% increase in inorganic carbon utilization was obtained coupled with 20%-30% increase in succinic acid selectivity. This was due to the promotion of the succinic acid branch of the glucose metabolism, while suppressing the pyruvate branch, along with the inhibition on the conversion from glucose to lactic acid. [Display omitted] [ABSTRACT FROM AUTHOR]

The list of standard abbreviations for JDS is available at adsa.org/jds-abbreviations-24. Nonstandard abbreviations are available in the Notes. Automated measurements of the ratio of concentrations of methane and carbon dioxide, [CH 4 ]:[CO 2 ], in breath from individual animals (the so-called "sniffer technique") and estimated CO 2 production can be used to estimate CH 4 production, provided that CO 2 production can be reliably calculated. This would allow CH 4 production from individual cows to be estimated in large cohorts of cows, whereby ranking of cows according to their CH 4 production might become possible and their values could be used for breeding of low CH 4 -emitting animals. Estimates of CO 2 production are typically based on predictions of heat production, which can be calculated from body weight (BW), energy-corrected milk yield, and days of pregnancy. The objectives of the present study were to develop predictions of CO 2 production directly from milk production, dietary, and animal variables, and furthermore to develop different models to be used for different scenarios, depending on available data. An international dataset with 2,244 records from individual lactating cows including CO 2 production and associated traits, as dry matter intake (DMI), diet composition, BW, milk production and composition, days in milk, and days pregnant, was compiled to constitute the training dataset. Research location and experiment nested within research location were included as random intercepts. The method of CO 2 production measurement (respiration chamber [RC] or GreenFeed [GF]) was confounded with research location, and therefore excluded from the model. In total, 3 models were developed based on the current training dataset: model 1 ("best model"), where all significant traits were included; model 2 ("on-farm model"), where DMI was excluded; and model 3 ("reduced on-farm model"), where both DMI and BW were excluded. Evaluation on test dat sets with either RC data (n = 103), GF data without additives (n = 478), or GF data only including observations where nitrate, 3-nitrooxypropanol (3-NOP), or a combination of nitrate and 3-NOP were fed to the cows (GF+: n = 295), showed good precision of the 3 models, illustrated by low slope bias both in absolute values (−0.22 to 0.097) and in percentage (0.049 to 4.89) of mean square error (MSE). However, the mean bias (MB) indicated systematic overprediction and underprediction of CO 2 production when the models were evaluated on the GF and the RC test datasets, respectively. To address this bias, the 3 models were evaluated on a modified test dataset, where the CO 2 production (g/d) was adjusted by subtracting (where measurements were obtained by RC) or adding absolute MB (where measurements were obtained by GF) from evaluation of the specific model on RC, GF, and GF+ test datasets. With this modification, the absolute values of MB and MB as percentage of MSE became negligible. In conclusion, the 3 models were precise in predicting CO 2 production from lactating dairy cows. [ABSTRACT FROM AUTHOR]

Global declines in animal populations suggest global causes. Herbivores are uniquely vulnerable to declines in the nutrient density of the plants they consume. CO 2 pollution is a global agent of nutrient dilution: the impoverishment of plant tissue, bite for bite, of the elements essential for herbivore survival. As plants assimilate higher levels of CO 2 , nutrient dilution can create flammable 'green deserts' of low-quality food for herbivores already limited by elements from nitrogen to sodium to zinc. We posit that nutrient dilution is a key driver – rich in testable predictions – of global declines in herbivore abundance. Its impact should be highest in productive and/or nutrient-poor ecosystems like tropical forests and the open oceans. It is reversed by fertilization. It acts regardless of habitat size or pesticide use. It thus complements these and other agents of herbivore decline. Nutrient dilution (ND) – the decrease in the concentration of nutritional elements in plant tissue – arises from an increase in the mass of carbohydrates and/or a decrease in the 20+ essential elements. Increasing CO 2 levels and its promotion of biomass are linked to nutrient dilution. We build a case for nutrient dilution as a key driver in global declines in herbivore abundance. Herbivores must build element-rich animal tissue from nutrient-poor plant tissue, and their abundance commonly increases with fertilization of both macro- and micronutrients. We predict the global impacts of nutrient dilution will be magnified in some of Earth's most biodiverse, highly productive, and/or nutrient-poor ecosystems and should favor specific traits of herbivores, including sap-feeding and ruminant microbiomes. [ABSTRACT FROM AUTHOR]

• An enhanced ejector-subcooler CO 2 transcritical refrigeration cycle is presented. • A parametric analysis and optimization of the enhanced cycle and the baseline cycle are carried out. • The results suggest the integration of the proposed cycle could achieve more compact and reliable systems. • The maximum COP improvements are computed as 11.7%-17.5% when the gas cooler outlet temperature ranges from 35 °C to 50 °C and the evaporating temperature is -40 °C. The main drawback associated with CO 2 refrigeration systems is related to their performance reduction during transcritical operation at warm climate conditions, which may be compensated by better cycle architectures such as the split-cycle with subcooling or the flash-tank configuration, among others. Specifically, the use of standard gas-ejectors together with parallel compressors provides even better efficiency improvements, not being able to use them with low-temperature evaporators to prevent the triple point inside the ejector. This paper proposes an enhanced cycle with a gas ejector for two-stage compressor architectures with vapor injection from the flash-tank, which is able to operate at low evaporating temperatures and that provides a greater performance improvement the more severe the climate conditions are. The methodology conducted is based on a thermodynamic analysis that includes parametric evaluation and cycle optimization, comparing the results to a conventional CO 2 transcritical cycle with flash-tank and dynamic vapor injection architecture. The main results show that a maximum Coefficient of Performance improvement of 17.5% is achievable for transcritical operation at -40 °C evaporating temperature. The compressor displacement capacity required with the enhanced cycle is up to 9% lower for the same refrigeration demand, reducing the electrical consumption as well as the compressor expenditure. Moreover, greater vapor injection mass flow rates are obtained by the gas-ejector injection with discharge temperature reductions up to 18%, enhancing the system reliability. [ABSTRACT FROM AUTHOR]

• Boiling coefficient increased with nozzle inlet pressure and specific enthalpy. • Boiling coefficient ranged from 300 to 4000 in the investigated trans-critical region. • Modified HNB showed an accuracy of 3 % in predicting the nozzle flow rates. • Proposed method for determining saturation pressure was superior to constant value. A modified homogeneous non-equilibrium boiling approach (HNB) was proposed for high-fidelity modelling of the trans-critical flashing process in two-phase R744 ejector nozzles. In the modified approach, the method of determining the metastable liquid saturation pressure was improved by integrating the metastable liquid enthalpy. Experimental tests were conducted on two different nozzles to calibrate the lumped accommodation coefficient in the modified HNB. The calibration dataset consisted of 30 trans-critical test points, with the motive inlet pressure ranging from 7.5 MPa to 11.5 MPa and temperature varying from 21 °C to 45 °C. It was demonstrated that the boiling coefficient was strongly related to nozzle inlet pressure and specific enthalpy. The coefficient was therefore fitted as a function of the operating condition. The modified HNB with the fitted function was then validated against another set of test data composed of 29 test points. The results demonstrated that the relative errors of the nozzle mass-flow rates were within 3 %. Finally, the modified HNB with the improved metastable liquid saturation pressure was compared and discussed with the existing HNB approach in the literature. [ABSTRACT FROM AUTHOR]

• The zoning simulation method was developed for CO 2 ejector. • Comparison of different numerical models for each section. • The zoning simulation can predict entrainment ratio more accurately. • Effects of geometries on performances of ejector were analyzed. In this paper, a novel simulation method (zoning simulation) for the CO 2 ejector containing lubricant oil is established. Firstly, the feasibility of the zoning simulation method is verified. Subsequently, the phase change model and turbulence model are selected for each section when using the zoning simulation method. The average relative discrepancy of entrainment ratio using zoning simulation is 8.696%, and the average relative discrepancy of entrainment ratio using overall simulation is 14.118%. The results demonstrate that the predicted entrainment ratio using zoning simulation outperforms entrainment ratio using overall simulation. Introducing the concepts of relative temperature and relative pressure, the average relative discrepancy of entrainment ratio using zoning simulation is reduced to 4.620 %, when both relative temperature and relative pressure greater than 1. [ABSTRACT FROM AUTHOR]

• A three-phase CO 2 /lubricant swirl ejector with swirl motive nozzle. • Heterogeneous mixture model developed for ejector with swirl motive nozzle. • Helical pitch and oil circulation ratio affect ejector performances. • Empirical correlation of entrainment ratio with swirl number. At present, most simulations of ejectors ignore the presence of lubricating oil, which may affect the accuracy of the results. Additionally, there has been less research conducted on the influence of motive nozzles with swirl generators on the performance of ejectors. In this study, a heterogeneous mixture model was developed for a three-phase swirl ejector equipped with a motive nozzle featuring a swirl generator. This article examines the performance of swirl ejectors under supercritical conditions using three-dimensional numerical simulations conducted in ANSYS. The study explores swirl ejectors with varying helical angles of 77°, 64°, 58°, 50°, 37°. The study also takes into account the influence of lubricating oil to enhance the practicality of the research. Firstly, lubricating oil with a volume fraction of 2 % was introduced into both the motive and suction streams, followed by conducting an ejection analysis. The results indicate that the swirl enhances the entrainment ratio, and the swirl strength can be modified by changing the helical angle. A smaller helical angle results in greater swirl strength and a higher entrainment ratio. When the helical angle is 37° and the helical pitch is 20 mm, a swirl number of 0.42, an entrainment ratio of 0.998, and an effective entrainment ratio of 0.863 is achieved. However, when the oil circulation ratio in the suction stream is increased from 2 % to 10 % while keeping the oil circulation ratio of the motive stream constant, the entrainment ratio decreases. [ABSTRACT FROM AUTHOR]

A R744 (CO 2) refrigeration system has been designed to cool down the Large Hadron Collider (LHC) silicon detectors ATLAS and CMS, located at CERN, Switzerland. The silicon detectors are subjected to high radiation levels. The system is composed of a pri- mary CO 2 trans-critical booster vapor compression loop operated with piston compressors, and an oil-free liquid pumped loop on the evaporation side, to preserve the detectors. To ensure the system's reliability, the cooling facility is designed to operate under a parallel operation mode of several modular 70 kW plant units providing evaporation temperature as low as -53 °C. This layout, is also useful in case of components failure and maintenance. A numerical model is developed using a dynamic simulation software Dymola that is based on the open source Modelica modelling language. The simulation results are proven on a first demonstration plant (System A) experimentally to explore the systems control logic and to validate the reliability of the system before it is built on the detectors side. In this paper the models development is explained and the results of the experimental validation of the numerical model are shown. [ABSTRACT FROM AUTHOR]

• Ejector cycles achieved higher performance than booster cycle within the gas cooler outlet temperature range of 31 and 50°C. • Multi-ejectors can be applied to ejector cycles with different configurations. • Up to 17% annual energy consumption reduction was found using ejector cycles. • Unit product exergy costs of ejector cycles are up to 28% lower than booster cycle. Restrictions on high-GWP refrigerants have made the use of transcritical CO 2 refrigeration systems widespread. Using transcritical booster refrigeration cycle in warm climates is unsatisfactory due to its high energy consumption. This paper presents theoretical analysis and performance comparison of three different transcritical CO 2 supermarket refrigeration cycle configurations with ejector expansion in Türkiye, which has different climatic regions. Bin-hour data were derived using hourly dry-bulb temperature values for provinces from 7 different regions in Türkiye. The applicability of multi-ejectors to each modeled cycle was also investigated. Annual energy consumption and environmental impact reductions of up to 17% were obtained using ejector expansion cycle compared to booster cycle. Ejector expansion cycles achieved higher performance than booster cycle up to 46% in terms of exergy efficiency at investigated ambient temperatures. Unit product exergy costs of the ejector cycles were found up to 28% lower than booster cycle. [Display omitted] [ABSTRACT FROM AUTHOR]

• Screening non-fluorinated refrigerants with low GWP and reduced flammability. • Performance criterion characterizing heating capacity for low-charge heat pumps. • The most attractive refrigerants were identified through decision-making techniques. • DME-CO 2 mixtures resulted in improvements in efficiency and levelized cost of heat. • Further investigations were recommended on mixtures with DME, Propylene and CO 2. The study investigated the characteristics of different natural refrigerants and their mixtures in a residential heat pump with low refrigerant charge. Three main evaluation criteria were utilized for comparing different mixtures: Coefficient of Performance (COP), Volumetric Heating Capacity (VHC), and a newly proposed indicator, the heating capacity at charge limit. Propane was used as a reference refrigerant. It was found that some mixtures significantly improved both COP and the heating capacity at charge limit while maintaining similar volumetric heating capacity and operating conditions. Alternative multi-criteria decision-making techniques were adopted to rank the best refrigerant mixtures. Mixtures rich in Dimethyl Ether (DME), such as DME-CO 2 [0.96-0.04] and DME-Propylene [0.75-0.25] were found consistently among the best options. Those were followed by Propylene-rich mixtures such as Propylene-CO 2 , Propylene-Isobutane and Propylene-Butane. The levelized cost of heat (LCOH) could be improved by up to 12 %. To accelerate the transition to natural refrigerants, without compromises on efficiency and costs, further research and certification activities on non-fluorinated refrigerants based on Dimethyl Ether (R-E170), CO 2 (R-744) and Propylene (R-1270) are recommended. [ABSTRACT FROM AUTHOR]

The isotopic fractionation of carbon between CO 2 gas and silicate melts is a crucial parameter to understand the carbon cycle at the planetary scale that requires accurate quantification. In this study, we conducted experiments to determine the carbon isotope fractionation between CO 2 gas and carbon dissolved in silicate melt at 350 – 420 MPa and 1160 – 1225 °C, across a range of melt compositions. A linear relationship emerges between the fractionation coefficient and the degree of polymerization of the melt (NBO/T; non–bridging oxygens per tetrahedral cation) with the fractionation coefficient increasing for depolymerized melts (e.g., basalt) and decreasing for polymerized melts (e.g., rhyolite): 1000 ln α gas - m e l t = 3.251 × N B O / T + 0.026 R 2 = 0.74 or 1000 ln α gas - m e l t = - 0.087 × Si O 2 + A l 2 O 3 w t % + 7.968 R 2 = 0.74 . These equations enable the calculation of carbon fractionation coefficients in silicate melts, providing a mean to interpret δ13C–value measurements in natural volcanic gases and melts through forward and backward modelling of degassing paths from mantle to surface. We hypothesize that the ratio of CO 3 2–/CO 2 dissolved in the melt is the key parameter behind this relationship. Carbon dissolved as CO 2 molecular transfers to the gas phase with a fractionation coefficient of 0 ‰ whilst carbon dissolved as CO 3 2– transfers with a fractionation coefficient of 2.9 ‰. The relationship is calibrated from NBO/T=0 to 0.88, covering most major melt compositions. However, at NBO/T>0.88, as the CO 3 2–/CO 2 ratio reaches its maximum in silicate melt, correspondingly the fractionation coefficient reaches its maximum of 2.9 ‰, both are expected to stabilize and remain constant. Carbon isotopic fractionation might hence offer a window into carbon speciation in natural melts. [ABSTRACT FROM AUTHOR]

Carbon dioxide-dependent Proteus mirabilis has been isolated from clinical specimens. It is not clear whether mutations in carbonic anhydrase are responsible for the carbon dioxide dependence of P. mirabilis. The pathogenicity of carbon dioxide-dependent P. mirabilis also remains unclear. The purpose of this study was to determine the cause carbon dioxide dependence of P. mirabilis and its pathogenicity. The DNA sequence of can encoding carbonic anhydrase of a carbon dioxide-dependent P. mirabilis small colony variant (SCV) isolate was analyzed. To confirm that impaired carbonic anhydrase activity is responsible for the formation of the carbon dioxide-dependent SCV phenotype of P. mirabilis , we performed complementation experiments using plasmids with intact can. Additionally, mouse infection experiments were performed to confirm the change in virulence due to the mutation of carbonic anhydrase. We found that the can gene of the carbon dioxide-dependent P. mirabilis SCV isolate showed had a frameshift mutation with a deletion of 1 bp (c. 173delC). The can of P. mirabilis encodes carbonic anhydrase was also found to function in Escherichia coli. The cause of the carbon dioxide-dependent SCV phenotype of P. mirabilis was an abnormality in carbonic anhydrase. Nevertheless, no changes were observed in virulence due to the mutation of carbonic anhydrase in mouse infection experiments. The can gene is essential for the growth of P. mirabilis in ambient air. The mechanisms underlying this fitness advantage in terms of infection warrant further investigation. [ABSTRACT FROM AUTHOR]

The current standard treatment for obstructive sleep apnea (OSA), continuous positive airway pressure (CPAP), is characterized by a low adherence rate due to various factors including circuit-dependent carbon dioxide (CO 2) rebreathing, which can exacerbated by disparate factors, such as low PAP, use of auto-titrating PAP or ramps. However, risk factors for rebreathing are often overlooked or poorly understood in clinical practice. Therefore, our objective was to evaluate the extent of rebreathing occurring with commonly used CPAP masks across varying PAPs, tidal volumes, and respiratory rates. In a bench study, we assessed the rebreathing rate of nine masks interfacing a CPAP with a lung simulator providing different breathing respiratory rates (15 or 20 breaths/min) and tidal volumes (400, 500, 600, 700 and 750 mL). Additionally, a theoretical model was developed to describe the likelihood of CO 2 rebreathing from four different masks at various breathing settings. Overall, all masks performed worse in situations characterized by low PAPs, high tidal volumes, and high respiratory rates. However, Dreamwear, Nuance, Siesta, Vitera, and particularly V2 masks exhibited greater susceptibility to rebreathing compared to F20, P10, Brevida, and Rio masks for the same variations of PAPs or ventilatory parameters. The mathematical model suggested that the risk of rebreathing for Rio, P10 and Nuance mask is negligible for respiratory rates of 10 breaths/min or below. Circuit-dependent CO 2 rebreathing can be a common occurrence and warrants careful mask selection upon CPAP therapy initiation for optimal clinical outcomes. • Circuit rebreathing may subtly affect CPAP adherence, yet is poorly investigated. • Mask models exhibit varied CO 2 rebreathing risks depending on different factors. • Higher rebreathing rates are at low PAPs, high tidal volumes/breathing frequencies. • Rebreathing risk is low for specific masks, perhaps apt for CPAP naïve patients. • Mask with higher rebreathing rates might be indicated for mask noise complaints. [ABSTRACT FROM AUTHOR]

Solid oxide cells (SOCs) are highly efficient energy conversion systems, offering switchable capabilities for power and fuel production. NiFe metal-supported structures in SOCs show promising advantages in structural stability and scalability. This study explores the synergistic effect of spontaneous Fe diffusion in NiFe-supported SOCs, enhancing alloy catalyst formation in the electrode and improving the sinterability of the zirconia-based electrolyte. This results in increased activity for carbon fuel reactions, resistance to coking, and a remarkably low ohmic resistance of 0.06 Ω cm2 at 800 °C. The NiFe support also enhances structural stability, enabling reversible and multifuel operation. The single cell achieves exceptional maximum power densities of 2.6 and 2.0 W cm−2 in fuel cell mode (3 % H 2 O/H 2 and dry CO) and current densities of − 1.51 and − 1.38 A cm−2 in electrolysis cell mode (1.3 V, 20 % H 2 O/H 2 and 20 % CO 2 /CO) at 800 °C, respectively. [Display omitted] [ABSTRACT FROM AUTHOR]

Solid oxide fuel cells (SOFCs), as important energy equipment, have excellent characteristics, including low pollution and high catalytic activity. The cathode, which is the key component of an SOFC, plays a vital role in practical applications. Herein, we study the properties of Ln 0.125 Sr 0.875 Co 0.875 Ta 0.125 O 3-δ (Ln = La, Sm, and Nd, abbreviated as LSCT, SSCT, and NSCT, respectively) cathode materials both theoretically and experimentally. The conductivity of LnSCT gradually decreased with decreasing Ln3+ ionic radius. Density of states (DOS) analysis indicated that LSCT has the highest conductivity owing to the band center of Co 3d being closer to O 1s. Density functional theory (DFT) calculations showed that the SSCT sample has the lowest oxygen vacancy formation energy, which facilitated the formation of oxygen vacancies. The binding energy results show that SSCT and NSCT have relatively good structural stability compared to LSCT. The polarization impedance values of LSCT, SSCT, and NSCT at 700 °C are 0.105, 0.069, and 0.304 Ω cm2, respectively. The CO 2 sensitivity of LSCT, SSCT, and NSCT was evaluated by calculating the CO 2 adsorption energy and performing impedance tests under different CO 2 concentrations. These results indicate that LSCT and SSCT have better CO 2 tolerance than NSCT. At 700 °C, for Ln = La, Sm, and Nd, the maximum power of NiCu-SDC/SDC/LSGM/LnSCT electrolyte-supported fuel cell reached 430, 462, and 382 mW cm−2, respectively. These findings provide a reference for the future design and development of SOFCs cathode material. [ABSTRACT FROM AUTHOR]

Syngas, a mixture of H 2 and CO with adjustable compositional ratios, can be directly produced via H 2 O/CO 2 co-electrolysis in solid oxide electrolysis cells (SOECs). In this study, We have developed a strategy to enhance the catalytic activity of titanate perovskite cathodes by constructing active metal-oxide interfaces through the in-situ growth of Ni x Cu 1-x alloy nanocatalysts (x = 0, 0.25, 0.5, 0.75 and 1) on LST matrix. The evenly distribution of Ni x Cu 1-x alloy nanoparticles (∼30 nm) on the LST substrate has been confirmed through a serious of characterization techniques, including XRD, XPS, SEM and TEM. Specifically, the LSTNi 0.75 Cu 0.25 cathode demonstrated an optimal synergistic effect, achieving high efficiency in the co-electrolysis of H 2 O/CO 2 to syngas. Under an applied voltage of 1.6 V at 800 °C, the syngas production rate reaches 5.43H 2 and 3.48 CO ml min−1 cm−2 with ∼96 % Faradaic efficiency. Furthermore, the composition of the produced syngas can be finely tuned in a broad range from 0.8 to 3.5 b y simply adjusting the inlet gas composition (H 2 O/CO 2 ratio) and the operating temperature. The LSTNi 0.75 Cu 0.25 cathode, when subjected to continuous H 2 O/CO 2 co-electrolysis for 100 h, exhibited remarkable stability, attributing to the robust and active nature of the metal-oxide interfaces. [ABSTRACT FROM AUTHOR]

To study the changes in dynamic compliance (C dyn), ventilation/perfusion (V ˙ / Q ˙) mismatch and haemodynamic variables in hypoxaemic anaesthetized horses whose PaO 2 increased following salbutamol inhalation. Retrospective, clinical, cohort study. A group of 73 client-owned horses treated with salbutamol when PaO 2 <100 mmHg (13.3 kPa) during anaesthesia. Horses were divided into two groups: responders (R), where PaO 2 after salbutamol ≥1.2 PaO 2 before treatment (i.e. ≥20% increase), and non-responders (NR), where PaO 2 after salbutamol <1.2 PaO 2 before treatment. Demographic data and intraoperative variables before treatment were compared between R and NR. C dyn , arterial to end-tidal carbon dioxide difference [P(a-E´)CO 2 ], estimated ratio of dead space to tidal volume (est.V D /V T), estimated shunt fraction (F-shunt), heart rate, systolic, mean and diastolic arterial pressure and dobutamine requirements were compared before and after treatment within R and NR. For each variable, the difference (Δ) between values pre- and posttreatment was calculated and compared between groups R and NR. Numerical data were compared using univariate or bivariate analysis and categorical data were compared using chi-square test; p < 0.05. Of the 73 horses 50 were classified as R while 23 horses were classified as NR. There was no statistical difference between R and NR for demographic data or initial intraoperative variables except for body weight [R: 531 (170–715) kg, NR: 540 (420–914) kg]. While salbutamol did not alter C dyn in either group, it significantly decreased P(a-E´)CO 2 , est.V D /V T and F-shunt in R only. ΔP(a-E´)CO 2 , Δest.V D /V T and ΔF-shunt were significantly greater in R (−17.8%, −19.0% and −24.1%, respectively) than in NR (11.5%, 6.6% and −0.3%, respectively). In hypoxaemic anaesthetized horses responding to inhaled salbutamol by a ≥1.2 increase in PaO 2 no change in C dyn was detected, but indicators of V ˙ / Q ˙ mismatch improved. [ABSTRACT FROM AUTHOR]

To compare static compliance of the respiratory system (C stRS) and the ratio of partial pressure of end-tidal to arterial carbon dioxide (P e′ CO 2 /PaCO 2), in healthy dogs using two approaches for tidal volume (V T) selection during volume-controlled ventilation: body mass based and driving pressure (ΔPaw) guided. Randomized, nonblinded, crossover, clinical trial. A total of 19 client-owned dogs anesthetized for castration and ovariohysterectomy. After a stable 10 minute baseline, each dog was mechanically ventilated with a V T selection strategy, randomized to a constant V T of 15 mL kg–1 of actual body mass (V TBW) or ΔPaw-guided V T (V TΔP) of 7–8 cmH 2 O. Both strategies used an inspiratory time of 1 second, 20% end-inspiratory pause, 4 cmH 2 O positive end-expiratory pressure and fraction of inspired oxygen of 0.4. Respiratory frequency was adjusted to maintain P e′ CO 2 between 35 and 40 mmHg. Respiratory mechanics, arterial blood gases and P e′ CO 2 /PaCO 2 were assessed. Continuous variables are presented as mean ± SD or median (interquartile range; quartiles 1–3), depending on distribution, and compared with Wilcoxon signed-rank tests. The V T was significantly higher in dogs ventilated with V TΔP than with V TBW strategy (17.20 ± 4.04 versus 15.03 ± 0.60 mL kg–1, p = 0.036). C stRS was significantly higher with V TΔP than with V TBW strategy [2.47 (1.86–2.86) versus 2.25 (1.79–2.58) mL cmH 2 O−1 kg–1, p = 0.011]. There were no differences in P e′ CO 2 /PaCO 2 between V TΔP and V TBW strategies (0.94 ± 0.06 versus 0.92 ± 0.06, p = 0.094). No discernible difference in ΔPaw was noted between the strategies. While no apparent difference was observed in the P e′ CO 2 /PaCO 2 between the V T selection strategies employed, C stRS significantly increased during the V TΔP approach. A future trial should explore if V TΔP improves perioperative gas exchange and prevents lung damage. [ABSTRACT FROM AUTHOR]

• Slight thermal damage to hair involving radiation but not flame was investigated. • TG/IR analysis and morphological characterization was coupled. • Microcracks appear at the hair shaft rather at the hair tip during short heat exposure. • Appearance of typical slight thermal damage on hair is probabilistic events. • The discrimination in hair thermal damage is helpful to analyze the suspect. To determine whether a suspect was in close contact with the fire source at a fire site through slight thermal damage to hair, a cone calorimeter was employed to simulate fire scene conditions as a standard radiant source. The research focused on analyzing the thermal behavior of black hair and delving into the morphological characteristics of hair exhibiting slight thermal damage. At temperatures exceeding 240 °C, the proteins within the hair began to degrade. This degradation, in conjunction with tension along the hair shaft resulting from water loss, led to the formation of microcracks that could be detected through scanning electron microscopy (SEM) but eluded observation with an optical microscope (OM). It is noteworthy that the initial slight thermal damage was regularly located at the hair shaft but not the hair tip, which should be the key parts when exanimating hairs without obvious thermal damage. Additionally, during very short exposure, the appearance of typical slight thermal damage on fire is probabilistic events. Along with the increase of temperature, the organic compounds in hair were thermally degraded into NH 3 , SCO and carbon CO 2, resulting in the typical traces of discoloration, expansion, blistering, and cracking presented at hair shafts and tips. The probability of encountering both slight and obvious thermal damage on hair increased with rising temperatures. By observing the traces on the easily overlooked part of the hair shaft, the research established a method to analyze and discriminate the slight thermal damage to hair at fire scene, which provide valuable references for confirming arson suspects. [ABSTRACT FROM AUTHOR]

Gas exchange is the main function of the lungs. Lungs have a large reserve for gas exchange. Oxygen and carbon dioxide diffuse along their partial pressure gradient across the alveolar–capillary membrane. Alveolar ventilation and pulmonary circulation are closely matched to provide efficient gas exchange in the lungs. Hypoxaemia often results from mismatch in ventilation–perfusion. Gas exchange can be impaired in various disease states. Measurement of the diffusing capacity for carbon monoxide (DLCO) provides estimation of the gas exchange function. A low DLCO indicates an impairment of oxygen transfer across the alveolar–capillary membrane. Based on the lung function tests one can assess the risks of perioperative pulmonary complications. Anaesthesia and surgery adversely affect pulmonary function, many of which adverse effects can be prevented. [ABSTRACT FROM AUTHOR]

In this contribution, the design of a graphene-supported high-entropy single-atom catalyst (HESAC) composed of Fe, Co, Ni, and Ru metal atoms (FeCoNiRu-HESAC) is proposed. Negative formation energy and positive dissociation potentials indicate such materials' thermodynamic and electrochemical stability. Based on density functional theory (DFT) calculations, Co active sites lead to the overpotentials of 0.28 V RHE for oxygen evolution reaction (OER), 0.16 V RHE for hydrogen evolution reaction (HER), and 0.25 V RHE for CO 2 reduction reaction (CO 2 RR) towards CO formation. These surpass the activity of CoN 4 single-atom catalyst. More interestingly, the low CO 2 RR and HER overpotentials enable the FeCoNiRu-HESAC to produce syngas (CO + H 2). In addition, the Fe, Ni, and Ru sites simply serve as counterparts to modify the performance of Co active sites through non-bonding interactions. Besides, machine learning (ML) implies that, the valence electrons of intermediates as well as the d orbital electrons of metal sites are the most important parameters affecting the reaction intermediates' Gibbs free energy. According to these DFT and ML results, a strategy to design multifunctional HESACs electrocatalysts is developed. [Display omitted] • DFT calculations performed on multifunctional FeCoNiRu-HESAC species. • FeCoNiRu-HESAC surpassed the OER, HER, and CO 2 RR activities of SAC. • Fe, Ni, and Ru served as counterparts enhancing OER, CO 2 RR, and HER activity of Co. • Low HER- and CO 2 RR-overpotentials enabled the FeCoNiRu-HESAC to produce syngas. • ML implied valence e− of intermediates & d orbital e− of catalyst active site as the key parameters. [ABSTRACT FROM AUTHOR]

The valence states of Cu site are regarded as an important factor affecting the performance of syngas to higher alcohols (C 2+ OH). Regrettably, the role of Cu0 and Cu+ in CO hydrogenation to higher alcohols remains controversial due to the complexity of the reaction. In this study, Cu0 and Cu 2 O powders are directly added as the precursors to adjust the ratios of Cu+/(Cu0+Cu+) and Cu particle sizes in CuZnAl catalysts by a complete liquid-phase (CLP) technology. The CAT-Cu0 catalyst with higher Cu0 content shows the highest CO conversion (>15%) ascribing to the biggest S Cu , but is also accompanied by the highest CO 2 selectivity (>40%), while the CAT-Cu+ catalysts with higher Cu+ content displays relative better C 2+ OH selectivity (>60%) and stability due to a higher probability of CO insertion. In-situ DRIFTS experiments reveal that a synergy between larger Cu particle sizes (30～40 nm) and surface Cu+ sites, in which larger Cu sizes enhances the probability of bridge CO adsorption, thereby favoring the C–O bond dissociation for CH x formation. Meanwhile, Cu+ active sites provide a higher probability for CO/CHO insertion to form CH 3 CHO*/CH 2 CO* intermediates. This study further deepens our understanding of the critical controlling factors for highly selective synthesis of C 2+ OH from syngas over Cu-based catalysts. • Catalytic performance was strongly related to Cu+/(Cu0+Cu+) ratios. • Cu + active site provided a higher probability for CO insertion. • Cu0 was more active than Cu + for water-gas shift reaction. • Larger Cu particles size favored the formation of CH x. [ABSTRACT FROM AUTHOR]