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Recently, we demonstrated that the local heating of degassed water can generate water vapor microbubbles and induce a rapid flow around the bubble. Although flow generation involves the self-excited oscillation of bubbles at a local heating point, the conditions under which the bubbles oscillate are not fully understood. In this study, the dependence of microbubble size and oscillation frequency on the concentration of non-condensable gases in water was investigated. A continuous-wave laser beam was focused on a β -FeSi 2 thin film, and water was locally heated using the photothermal conversion properties of the film. The results showed that the lower the concentration of non-condensable gases dissolved in water, the smaller the bubble size and the higher the oscillation frequency. Furthermore, it was found that the bubbles oscillate when the amount of non-condensable gas absorbed by the bubbles, i.e., the bubble size, falls below a specific level. This study can provide a new understanding of the bubble oscillation mechanism and lead to the development of fluid control technology using bubbles. [ABSTRACT FROM AUTHOR]

Tight sandstone water-bearing gas reservoirs typically exhibit low porosity and low permeability, with reservoir rocks characterized by complex pore structures, often featuring micron-scale or smaller pore throats. This intricate reservoir structure significantly restricts fluid flow within the reservoir, necessitating a certain threshold pressure gradient (TPG) to be overcome before flow can commence. This study focuses on the Ordos Basin and explores the influence of high water content tight sandstone gas reservoirs on TPG under different water saturation and formation pressure conditions through experiments. A mathematical model of TPG is established using multiple linear regression method. The results show that TPG is primarily affected by water saturation, followed by formation pressure. As the water saturation increases, the TPG of the core decreases, and the change becomes more pronounced when the water saturation exceeds 50%. As formation pressure increases, the weakening of the slippage effect in gas molecules leads to TPG stabilization, especially when local pressure exceeds 25.0 MPa. The research also shows that low-permeability cores exhibit greater TPG variation with pressure changes, while high-permeability cores remain more stable. A mathematical model was developed and validated to predict TPG based on permeability, water saturation, and formation pressure. These findings highlight the need to monitor formation water content during tight sandstone gas reservoir development to optimize production strategies, providing valuable insights for improving reservoir management and guiding future research. [ABSTRACT FROM AUTHOR]

In this study, we utilized various Pr‐doped CeO2 catalysts (Pr=5, 10, 20, and 30 wt.%) as a support medium for the dispersion of cobalt (Co) nanoparticles, aiming to investigate the impact of oxygen vacancies on the water‐gas shift (WGS) reaction. Different characterization techniques were employed to understand the insights into the structure‐activity relationship governing the performance of Pr doped ceria supported Co catalysts towards WGS reaction. Our findings reveal that Co/Pr‐CeO2 catalysts at optimum Pr loading (10 wt.%) exhibit a superior CO conversion (88 %) facilitated by the presence of more oxygen vacancies induced by Pr doping into the CeO2 lattice, as opposed to the performance of the pure Co/CeO2 catalytic system. It was also found that the highest activity was obtained at increased intrinsic oxygen vacancies and strong synergy between Co and Pr/CeO2 support, fostering more favorable CO activation at the interfacial sites, thus accounting for the observed enhanced activity. [ABSTRACT FROM AUTHOR]

Acrylamide, a probable human carcinogen present in heat-processed foods and environmental contaminants, requires sample extraction and preconcentration before chromatographic analysis. The method developed in this study employed derivatization with xanthydrol and dispersive liquid–liquid microextraction utilizing low-density anisole. Durian or potato chips were combined with deionized water, defatted with hexane, and subjected to precipitation of soluble carbohydrates and proteins using clarification reagents. Water samples were filtered through a membrane filter. Acrylamide was derivatized by introducing an acidic methanolic solution of xanthydrol at 50 °C. The derivatized acrylamide was extracted with 70 µL of anisole and vortexed, with the methanol from the xanthydrol solution serving as the disperser solvent. The anisole layer was analyzed using gas chromatography with both flame ionization and mass spectrometric detection. Linear calibration plots exhibited coefficients of determination >0.9997. The precision was measured at <10% RSD, and recoveries ranged from 84% to 107%. The quantitation limit varied from 2 to 10 µg kg−1 for processed chips and from 0.05 to 0.10 µg L−1 for water samples. Acrylamide was detected in all processed chip samples, with some concentrations exceeding the benchmark value of 750 μg kg−1. However, no acrylamide was identified in any of the water samples. [ABSTRACT FROM AUTHOR]

Energy transitions are reshaping hydrosocial relations. How they will be reshaped, however, depends on location and water's material relationship to other resources and industrial activities embedded within energy transitions. To highlight this, we focus on three different resources—coal, natural gas, and lithium—to signal how the water–energy nexus will be reworked in a transition away from fossil fuels. We examine the water–coal nexus as an example of a resource relationship that is transitioning out, or that is being moved away from in the green energy transition. Natural gas represents the "bridge fuel" used through the transition. Lithium illustrates a resource inside the green transition, as it is a fundamental material for green technologies in the transition to a low‐carbon future. Coal, natural gas, and lithium each have their own material impacts to water resources that stem from their industrial lifecycle and different implications for communities shaped by coal, natural gas, and lithium activities. To explore this, we review each of these resources' connection to water, their legal and regulatory dimensions, and their impact on communities and water justice. We argue that the energy transition is also a hydrosocial transition that will create uneven water‐related benefits and burdens. To maximize sustainability and equity, efforts to decarbonize energy systems must examine the localized, place‐based hydrosocial relations that differentially affect communities. This article is categorized under:Engineering Water > Planning WaterHuman Water > Water GovernanceHuman Water > Rights to Water [ABSTRACT FROM AUTHOR]

Copper‐doped ceria (CuCeO2) catalysts with 0–26.5 Cu/(Cu+Ce) at% were synthesized via the reverse microemulsion method. X‐ray diffraction analysis of freshly synthesized and spent (post‐reaction) catalysts showed no separate phase of copper or copper oxide, indicating that Cu was incorporated into the CeO2 lattice, replacing Ce. Temperature programmed desorption experiments showed that the activation energy of CO2 desorption increased for higher Cu loadings, indicating stronger CO2 adsorption. This phenomenon was attributed to enhanced formation of oxygen vacancies due to Cu doping. X‐ray photoelectron spectroscopy further confirmed the enhanced generation of oxygen vacancies due to Cu incorporation. Catalytic performance evaluation with the H2/CO2 feed in the 300–600 °C range showed that all catalysts were 100 % selective to CO generation, with higher Cu loadings resulting in CO2 conversion close to equilibrium values at 500–600 °C. The activation energy of the reaction, determined through reaction tests, exhibited inverse relationship with the activation energy of CO2 desorption. The relationship between these two energy barriers is explored, providing valuable insights into the mechanism of RWGS activity enhancement. [ABSTRACT FROM AUTHOR]

Efficient heterogeneous catalyst design primarily focuses on engineering the active sites or supports, often neglecting the impact of trace impurities on catalytic performance. Herein, we demonstrate that even trace amounts of sulfate (SO42−) residuals on Ru/TiO2 can totally change the CO2 reduction from methanation to reverse-water gas shift (RWGS) reaction under atmospheric pressure. We reveal that air annealing causes the trace amount of SO42− to migrate from TiO2 to Ru/TiO2 interface, leading to the significant changes in product selectivity from CH4 to CO. Detailed characterizations and DFT calculations show that the sulfate at Ru/TiO2 interface notably enhances the H transfer from Ru particles to the TiO2 support, weakening the CO intermediate activation on Ru particles and inhibiting the further hydrogenation of CO to CH4. This discovery highlights the vital role of trace impurities in CO2 hydrogenation reaction, and also provides broad implications for the design and development of more efficient and selective heterogeneous catalysts. The impact of trace impurities on catalytic performance is often overlooked. Here the authors show that trace amounts of sulfate residuals on Ru/TiO2 substantially enhance hydrogen transfer from Ru particles to the TiO2 support, shifting CO2 reduction from methanation to the reverse water-gas shift reaction. [ABSTRACT FROM AUTHOR]

In order to study the changes in two‐phase flow parameters after pipeline damage and the impact of gas injection on water leakage from damaged pipelines, experimental and simulation studies were conducted on the damaged pipelines. The main objective is to compare the void fraction in intact and damaged states and to investigate the factors influencing and variations in gas–liquid leakage flow rates. The results show that increasing the liquid superficial velocity can reduce the difference in void fraction distribution caused by different damage directions. The leakage flow rate is affected by the direction of damage and the superficial velocity of the respective phase. It has been discovered that gas injection in the pipeline can make it easier to find small‐area pipeline damage. The change rate of the volume void fraction shows different changes with the increase in gas proportion in different directions; the shape of the bubble has no bearing on this change. [ABSTRACT FROM AUTHOR]

The synthesis of K-promoted ZnO/ZnAl 2 O 4 nanocomposite catalyst for high temperature water gas shift (HT-WGS) via novel eco-friendly route using CO 2 as key reagent has been studied. The sodium and nitrate-free precursors of the Zn–Al spinels (ZnO/ZnAl 2 O 4) were successfully prepared by saturation of ZnO–AlOOH aqueous suspension with CO 2 , followed by thermal treatment and potassium deposition. The effect of the calcination temperature of precursor on the acid-base and textural properties, surface morphology and activity of catalysts was investigated. Nanocomposites calcined at 500–600 °C displayed higher basicity and specific surface area than samples calcined at temperature above 600 °C. At the same time, the high and stable activity of K–ZnO/ZnAl 2 O 4 catalysts toward HT-WGS was revealed for the nanocomposite. The catalysts exhibit high and stable activity and their selectivity is significantly higher than that of conventional systems for HT-WGS. Both at higher steam-to-carbon and also at lower H 2 O/C molar ratios, no methane formation was observed under HT-WGS conditions in the presence of ZnAl_X_K catalysts. [Display omitted] • Simple and eco-friendly route of catalyst synthesis using CO 2 as key reagent. • Great effect of the calcination temperature of ZnO–ZnAl 2 O 4 on textural properties and surface morphology. • Catalyst activity depends on the calcination temperature of ZnO–ZnAl 2 O 4 nanocomposite. • Higher selectivity of novel HT-WGS catalyst at lower steam-to-carbon ratio. [ABSTRACT FROM AUTHOR]

Summary In the face of anthropogenic warming, drought poses an escalating threat to food production. C4 plants offer promise in addressing this threat. C4 leaves operate a biochemical CO2 concentrating mechanism that exchanges metabolites between two partially isolated compartments (mesophyll and bundle sheath), which confers high‐productivity potential in hot climates boosting water use efficiency. However, when C4 leaves experience dehydration, photosynthesis plummets. This paper explores the physiological mechanisms behind this decline. In a fast dehydration experiment, we measured the fluxes and isotopic composition of water and CO2 in the gas exchanged by leaves, and we interpreted results using a novel biochemical model and analysis of elasticity. Our findings show that, while CO2 supply to the mesophyll and to the bundle sheath persisted during dehydration, there was a decrease in CO2 conductance at the bundle sheath‐mesophyll interface. We interpret this as causing a slowdown of intercellular metabolite exchange – an essential feature of C4 photosynthesis. This would impede the supply of reducing power to the bundle sheath, leading to phosphoglycerate accumulation and feedback inhibition of Rubisco carboxylation. The interplay between this rapid sensitivity and the effectiveness of coping strategies that C4 plants deploy may be an overlooked driver of their competitive performance. [ABSTRACT FROM AUTHOR]

High conversion rate and selectivity are challenges for CO2 utilization through catalytic reverse water gas shift (RWGS) reaction. Herein, a novel mesoporous biochar (MB) supported Cu-Mo2C nano-interface was prepared by consecutive physical activation of coconut shells followed by carbothermal hydrogen reduction of bimetal. As compared with traditional carbon materials, this MB exhibited ultra-high specific surface area (2693 m2 g–1) and mesopore volume of mesopore (0.81 cm3 g–1) with a narrow distribution (2–5 nm), responsible for the high dispersion of binary Cu-Mo2C sites, CO2 adsorption and mass transfer in the reaction system. Moderate carbothermal reduction led to the sufficient reduction of Mo ion with carbon matrix of MB and dispersive growth of nano Cu-Mo2C binary sites (~ 6.1 nm) on the surface of MB. Cu+ species were formed from Cu0 via electron transfer and showed high dispersion with simultaneous boosted bimetal loading due to the strong interaction between nano Mo2C and Cu. These were advantageous to the intrinsic activity and stability of the Cu-Mo2C binary sites and their accessibility to the reactant molecules. Under the RWGS reaction conditions of 500 °C, atmospheric pressure, and 300,000 ml/g/h gas hour space velocity, the CO2 conversion rate over Cu-Mo2C/MB reached 27.74 × 10–5 molCO2/gcat/s at very low H2 partial pressure, which was more than twice that over traditional carbon supported Cu-Mo2C catalysts. In addition, this catalyst exhibited 99.08% CO selectivity and high stability for more than 50 h without a decrease in activity and selectivity. This study offers a new development strategy and a promising candidate for industrial RWGS. Highlights: Coconut shell derived ordered mesoporous biochar with ultra-high SBET and mesopore volume was fabricated. Mesoporous biochar facilitates nano Cu-Mo2C interface formation, CO2 adsorption and mass transfer. Strong interaction between Mo2C and Cu leads to electron transfer and anchoring of Cu. CO2 conversion rate over Cu-Mo2C/MB was twice that over Cu-Mo2C/traditional carbon. The catalyst exhibited 99.1% CO selectivity and high stability for more than 50 h. [ABSTRACT FROM AUTHOR]

This study investigates the effect of thermal treatment on the composition and morphology of cobalt oxide nanofibers synthesized via electrospinning. Cobalt acetate tetrahydrate and poly (vinyl alcohol) were used as precursors to produce cobalt acetate/poly(vinyl alcohol) nanofiber mats. The electrospun mats were subjected to various thermal treatments, including calcination in air at 500∘C, calcination under argon at 700∘C and 850∘C and treatment with water gas (CO and H2) at 180∘C. Scanning electron microscopy, transmission electron microscopy and X-ray diffraction were employed to characterize the nanofibers. The results demonstrated that the polycondensation tendency of cobalt acetate and the supportive properties of poly(vinyl alcohol) led to the maintenance of nanofibrous morphology across all thermal treatments. Calcination in air produced dense, highly crystalline Co3O4 nanofibers. In contrast, calcination under argon at 700∘C resulted in an amorphous carbon matrix embedded with small cobalt-based nanoparticles, while at 850∘C, the nanofibers contained larger, highly crystalline cobalt nanoparticles. Thermal treatment with water gas transformed the nanofibers into nano-belts primarily composed of crystalline CoO and Co3O4, with minimal amorphous phase. This study highlights the critical influence of thermal treatment on the structural and compositional properties of cobalt-based nanofibers, offering insights for tailoring these materials for applications in catalysis, energy storage and electronic devices. The findings emphasize the potential of controlled thermal strategies to produce diverse cobalt-based nanostructures with distinct properties. [ABSTRACT FROM AUTHOR]

Inland waters are important sources of the greenhouse gases carbon dioxide (CO2) and methane (CH4). Ponds have amongst the highest CO2 and CH4 fluxes of all aquatic ecosystems, yet seasonal variation in fluxes remain poorly characterized, creating challenges for accurately estimating annual emissions. Further, ponds can exhibit a range of mixing regimes, yet the impact of mixing regimes on gas emissions remains unclear. Here, we assessed annual dynamics of CO2 and CH4 in four temperate ponds (Minnesota, USA) that varied in mixing regimes. The ponds ranged from annual sinks to sources of CO2 (−1 to 15 mol m−2 yr−1) and were all significant sources of CH4 (4.3–8.2 mol m−2 yr−1), with annual fluxes in CO2 equivalents of 1.8–4.1 kg CO2-eq. m−2 yr−1. Mixing regimes impacted CO2 and CH4 dynamics, as stratified periods were associated with more anoxia, greater accumulation of gases in the bottom waters, higher emissions of CH4, and lower fluxes of CO2. Ponds with stronger summer stratification also had increased CO2 and CH4 fluxes associated with fall turnover. Overall, the two ponds with the strongest stratification had higher annual fluxes (2.6, 4.1 kg CO2-eq. m−2 yr−1) compared to the two ponds that more frequently mixed (1.8, 2.2 kg CO2-eq. m−2 yr−1). [ABSTRACT FROM AUTHOR]

The burgeoning environmental crisis and the urgent need for sustainable energy solutions underscore the importance of innovative waste-to-energy conversion technologies. This study aims to an efficient utilize of face mask waste for a novel energy system to address waste management and energy production simultaneously by introducing an integrated system comprising a gasifier reactor, steam methane reformer, and water-gas shift reactor, designed to convert face mask waste into a hydrogen-rich syngas. The gasifier reactor initiates the process with a hydrogen flow rate of 2.352 mol/h, which is subsequently enriched to 5.405 mol/h in the steam methane reformer and further to 6.132 mol/h in the water-gas shift reactor, marking a cumulative increase of 160%. Methane content, initially at 2.017 mol/h, is reduced by 38.4% post-reforming and remains stable through the water-gas shift reaction. Carbon monoxide sees a significant reduction from 0.8558 mol/h to 0.1817 mol/h, a decrease of 78.8%. The findings of this study have profound implications for the energy sector, demonstrating the potential of the integrated system to not only mitigate waste but also to produce clean energy efficiently. The substantial increase in hydrogen content across the reactors highlights the system's capability to support the burgeoning hydrogen economy, while the management of carbon oxides aligns with environmental sustainability goals. The value of this study lies in its contribution to the advancement of waste-to-energy technologies and its role in shaping future energy policies and practices. • An innovative waste-to-energy conversion technology is developed. • Face mask waste gasification is integrated with SMR and WGSR. • Hydrogen flow rate in the gasifier is 2.352 mol/h. • Hydrogen flow rate is increased to 5.405 mol/h in SMR and 6.132 mol/h in WGSR. • This integration improves the hydrogen flow rate by 160%. [ABSTRACT FROM AUTHOR]

The resistivity difference between oil and gas layers and the water layers in low contrast tight sandstone reservoirs is subtle. Fluid identification and saturation calculation based on conventional logging methods are facing challenges in such reservoirs. In this paper, a new method is proposed for fluid identification and saturation calculation in low contrast tight sandstone reservoirs. First, a model for calculating apparent formation water resistivity is constructed, which takes into account the influence of shale on the resistivity calculation and avoids apparent formation water resistivity abnormal values. Based on the distribution of the apparent formation water resistivity obtained by the new model, the water spectrum is determined for fluid identification in low contrast tight sandstone reservoirs. Following this, according to the average, standard deviation, and endpoints of the water spectrum, a new four-parameter model for calculating reservoir oil and gas saturation is built. The methods proposed in this paper are applied to the low contrast tight sandstone reservoirs in the Q4 formation of the X53 block and X70 block in the south of Songliao Basin, China. The results show that the water spectrum method can effectively distinguish oil-water layers and water layers in the study area. The standard deviation of the water spectrum in the oil-water layer is generally greater than that in the water layer. The new fourparameter model yields more accurate oil and gas saturation. These findings verify the effectiveness of the proposed methods. [ABSTRACT FROM AUTHOR]

Carbonate reservoirs exhibit varying pore sizes that significantly impact gas distribution and flow dynamics. Current models fail to adequately address the flow mechanisms within the diverse matrix pores of carbonate reservoirs. To address this gap, we propose a triple-porosity model that incorporates small pores, large pores, and fractures, alongside a capillary pressure equation that accounts for pore radius and saturation. Additionally, a new transient shape factor was derived. Utilizing the triple-porosity model, we investigated the processes of gas separation and dissolution from oil, gas distribution, and the effects of gas on water flow. Our findings reveal that gas is primarily dissolved during the initial water injection stage or at low gas saturation levels. Once the pressure reaches the gas initiation threshold, gas transport becomes the dominant mechanism. Both dissolution and transport can reduce gas saturation by a factor of 1:10. In small pores, capillary pressure induces a gas locking phenomenon, resulting in higher free gas presence compared to large pores. Moreover, the presence of the gas phase accelerates the spread of injected water. Implementing depletion followed by water injection decreases oil recovery. This study elucidates the processes of gas separation, distribution, flow, and dissolution, providing theoretical guidance for managing complex flow dynamics in volatile carbonate reservoirs. [ABSTRACT FROM AUTHOR]

A series of experiments have been performed studying the displacement of water by gas in consolidated porous media at an adverse viscosity ratio of μw/μg = 100, from the perspective of subsurface gas storage. The gas/water relative permeability functions (RPs) produced in the laboratory to model these processes generally use short cores from which the RPs are derived using conventional analysis and assumptions. In this work, we present results that challenge some of these assumptions and bring into question some of the currently used RP functions to design storage scenarios gas/water systems. Using a novel visualization technique, large two-dimensional sandstone slabs are imaged via x-rays during the gas → water unstable drainage processes. Three experiments were carried out evaluating the impact of rate and vertical flow direction. In the bottom-to-top experiments, we observed the rate dependence on the evolution of viscous fingers from an initially stable bank resulting from the effect of capillary dispersion stabilizing the early finger growth. In the case of top-to-bottom displacement, we observe that the combined capillary and gravity forces are not sufficient to fully stabilize the system, although a visible "stable" bank is formed prior to the emergence of the gas fingering instability. Finally, these results are compared to a water → oil drainage carried out under the same conditions and viscosity ratio. The results are then discussed in the context of subsurface gas storage, and recommendations are made for future experiments designed to derive appropriate gas/water RP functions and for upscaling the results from the laboratory to the field. [ABSTRACT FROM AUTHOR]

The Lower Cretaceous Manville Group of Upper McMurray Formation is one of the main bitumen reservoirs in Athabasca. In this study, the relationship between reservoirs heterogeneity and bitumen geochemical characteristics were analyzed through core and microscopic observation, lab analysis, petrophysics and logging data. Based on the sedimentology framework, the formation environment of high‐quality oil sand reservoirs and their significance for development were discussed. The results indicate that four types lithofacies were recognized in the Upper McMurray Formation based on their depositional characteristics. Each lithofacies reservoirs has unique physical properties, and is subject to varying degrees of degradation, resulting in diversity of bitumen content and geochemical composition. The tidal bar (TB) or tidal channel (TC) facies reservoir have excellent physical properties, which are evaluated as gas or water intervals due to strong degradation. The reservoir of sand bar (SB) facies was evaluated as oil intervals, due to its poor physical properties and weak degradation. The reservoir of mixed flat (MF) facies is composed of sand intercalated with laminated shale, which is evaluated as poor oil intervals due to its poor connectivity. The shale content in oil sand reservoir is very important for the reservoir physical properties and bitumen degradation degree. In the context of regional biodegradation, oil sand reservoirs with good physical properties will suffer from strong degradation, while oil sand reservoirs with relatively poor physical properties are more conducive to the bitumen preservation. [ABSTRACT FROM AUTHOR]

Reducing carbon dioxide emissions is one of the largest energy and environmental challenges currently faced globally. To achieve carbon neutrality, the development of new technologies and simultaneous improvement of conventional technologies are required. Catalysis, which determines the success or failure and efficiency of the process, is at the center of addressing these problems. Innovative advancements in catalysis have been accomplished through the extensive research on catalytic materials. Oxygen storage materials with oxygen storage capacity (OSC) have been widely applied in supports and active cocatalysts for energy and environmental catalytic applications. This review provides knowledge on the extended applications (reforming, water-gas shift reaction, and partial oxidation of methane (POM) for high-value-added chemicals, including hydrogen production, deoxygenation of fatty acids for second-generation biofuel production, selective catalytic reduction of NOx with NH3, hydrocarbon (HCs) oxidation for emission control, CO oxidation for vehicle exhaust control and purification of gaseous product fuel, and soot oxidation for the removal of motor-type pollutants) of these materials, which are mainly used as three-way catalysts (TWC) in automotive catalysis, to the carbon-neutral field. In particular, this study focuses on the physico-chemical properties that are closely synergistic with OSC, such as reducibility, dispersion, surface acid/base properties, and physical properties, such as surface structure or morphology. [ABSTRACT FROM AUTHOR]

The sorption‐enhanced water gas shift (SEWGS) process has emerged as a promising technology for high‐purity H2 production. MgO serves as a competitive sorbent in SEWGS, removing CO2 in situ. Yet the reaction mechanism of SEWGS employing MgO is not well understood. In this work, the reaction mechanism of SEWGS on the MgO surface is revealed by density functional theory (DFT) analysis. The MgO(110) surface shows a remarkable enhancement for SEWGS. Spontaneous dissociation of H2O is observed whether in the presence of CO or CO2, leading to the enrichment of hydroxyl groups for subsequent reactions. CO2 generated is captured by surface basic sites, resulting in the formation of MgCO3. The presence of the generated hydroxyl group enhances the dehydrogenation reaction on the surface, facilitating hydrogen production. The reaction pathway is described as follows. First, spontaneous dissociation of H2O occurs when co‐adsorbed with CO on the MgO surface. Then, two hydroxyl groups interact, yielding atomic O for CO oxidization and atomic H for H2 generation. Ultimately, CO2 is captured by the surface while H2 desorbs from the surface. The rate‐limiting step is H2 generation with an energy barrier of 0.68 eV. The calculation results elucidate the enhancement mechanism of MgO on the SEWGS process. [ABSTRACT FROM AUTHOR]

Water management is important for addressing the challenges posed by next‐generation fuel cell electric vehicles. Although X‐ray imaging techniques are useful for probing the mechanism of water transport in the gas diffusion layer of polymer electrolyte fuel cells, they cannot be easily applied to the Pt‐loading catalyst layer because of its low X‐ray transmittance due to the high absorption coefficient of Pt. Herein, a method to realize the high‐resolution X‐ray imaging of a 30 μm‐thick cathode catalyst layer in polymer electrolyte fuel cells using synchrotron X‐ray radiography is proposed, thus bridging the above gap. The results of operando synchrotron X‐ray radiography measurements reveal that water accumulation in the cathode catalyst layer depends on the cell temperature, feed gas humidity, and cell voltage, while time‐slice analysis shows that the water accumulation rate in the cathode catalyst layer immediately after the power generation is faster than that in the cathode gas diffusion layer. The proposed imaging method can be used to evaluate the water storage capacity of the catalyst layer and thus deepen the understanding of flooding phenomena and cold‐start behavior at subzero temperatures. [ABSTRACT FROM AUTHOR]

Copyright of Low-Carbon Chemistry & Chemical Engineering is the property of Low-Carbon Chemistry & Chemical Engineering Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

In response to the imperative for sustainable iron production with reduced CO2 emissions, this study delves into the intricate role of TiO2 in the direct reduction of iron oxide pellets. The TiO2-dependent reducibility of iron oxide pellets utilizing H2 and CO gas across varied temperatures and gas compositions is thoroughly investigated. Our findings unveil the nuanced nature of the TiO2 effect, underscored by its concentration-dependent behavior, revealing an optimal range between 1 and 1.5 pct TiO2, where a neutral or positive impact on reduction kinetics and diffusion coefficient is observed. Notably, the synergistic interplay of CO and H2 at 1000 °C emerges as particularly efficacious, suggesting complementary effects on the reduction process. The introduction of H2 into the reducing atmosphere regulated by CO not only extends the transition range but also markedly expedites the rate of reduction. Furthermore, our study highlights the temperature sensitivity of the TiO2 effect, with higher TiO2 content correlating with prolonged reduction time in a 100 pct H2 atmosphere at 900 °C. In a 100 pct H2 atmosphere, the non-contributory role of TiO2 stems from the water-gas shift reaction. Conversely, introducing H2 into a CO-controlled reducing atmosphere with TiO2 enhances the transition range and expedites the reduction rate. Additionally, our findings underscore the role of total iron content, revealing a direct correlation with the reduction process. [ABSTRACT FROM AUTHOR]

Copyright of Petroleum Geology & Oilfield Development in Daqing is the property of Editorial Department of Petroleum Geology & Oilfield Development in Daqing and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Natural Gas Geoscience is the property of Natural Gas Geoscience and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Modification reaction of lignite in subcritical H2O–CO system can significantly increase its caking index to more than 90. Separating and extracting the caking components from modified lignite, exploring the formation path of caking components, and establishing a kinetic model for the generation of these components are of significant importance for lignite hydrogenation reaction control. The lignite modified reaction was carried out in subcritical D2O–CO systems using the isotope tracer method. The formation path of caking components was defined by solvent extraction–IRMS–GPC combination technology. The results show that the soluble substances of tetrahydrofuran (TS) and benzene (BS) are the main caking components causing the structural transformation of lignite (A). The separation of n-hexane soluble (NS) also has an effect on the caking index of the modified coal. In the hydrogenation caking component formation stage, the lignite pyrolysis fragments combine with active hydrogen generated by water gas shift reaction to form caking substances, that is, A → TS + BS + NS. The formation activation energy of caking components is in the range of 0.39–58.24 kJ/mol. In the polycondensation caking component conversion stage, three soluble substances are converted in the order of TS → BS → NS, and the activation energy for the formation of caking components is 31.710–57.616 kJ/mol. [ABSTRACT FROM AUTHOR]

In-depth understanding of the gas–water seepage law caused by different degrees of gas layer perforation and varying gas production rates is key to determining a reasonable development technology policy for vertical heterogeneous edge-water gas reservoirs. Based on core physical data from the entire section of the X2 well, a large-scale high-pressure positive-rhythm profile model that takes into account the influence of "discontinuous interlayer" was innovatively established. The water intrusion process of the gas layer profile under different gas production rates and degrees of gas layer perforation was simulated using an electrical resistivity scanning device. The experimental model has an area of 3000 cm2, with a maximum pressure of 70 MPa and a maximum temperature resistance of 150 °C. It includes 456 evenly distributed fluid saturation test points to accurately monitor the gas–water distribution, addressing the issues of small bearing pressure and insufficient saturation monitoring points found in other large-scale models. The experimental results show that, in heterogeneous reservoirs, the high-permeability zone controls the invasion path of edge water, which is the main reason for the uneven invasion of edge water. For the positive-rhythm profile of the F layer, a higher gas production rate (1000 mL/min) shortens the water-free gas recovery period of the gas well and reduces the recovery rate. Perforating the upper two-thirds of the layer can inhibit edge-water breakthrough, prolong the water-free gas recovery period of the gas well, enable the gas–water interface to advance more uniformly, and enhance the recovery degree. The results of this study greatly enhance our understanding of the water invasion characteristics of positive-rhythm reservoirs under the influence of different gas production rates and varying degrees of gas layer perforation. [ABSTRACT FROM AUTHOR]

As a highly efficient and environmentally friendly gas fuel, hydrogen has emerged as one of the most promising sources of energy. However, the hydrogen explosion limit is low, the explosion risk is high, and the production, storage and transportation processes are prone to explode. Therefore, it is necessary to explore hydrogen explosion inhibitor to prevent and mitigation hydrogen explosions. In this study, the synergistic effect of the combination of inert gas and ultrafine water mist on the suppression of hydrogen explosion was studied by using a standard 20 L spherical explosive container bomb. The results of the study indicate that the combined use of inert gas and ultrafine water mist yields better suppression effects in terms of explosion pressure, flame propagation speed, and flame cellular structure formation, compared to the use of a single inert gas. Inert gas and ultrafine water mist have synergistic effects, but the synergistic effect of N 2 was significantly stronger than that of CO 2. Through chemical kinetic simulation, it was found that the formation rate of O, H, and OH, which were three active free radicals, decreased significantly compared with that of the single inhibition condition in the process of inhibiting the hydrogen explosion reaction by inert gas and ultrafine water mist. The pairing of nitrogen with ultrafine water mist demonstrates a superior collaborative effect in comparison to the combination of carbon dioxide and ultrafine water mist. • Synergistic explosion suppression effect of inert gas and ultra-fine water mist. • Twin-fluid can effectively slow down the formation of flame honeycomb structures. • Analyzed the synergistic explosion suppression mechanism of twin-fluid. • N 2 is more synergistic than CO 2 with ultra-fine water mist. [ABSTRACT FROM AUTHOR]

The concentration of hydrogen in oxygen (HTO) is a crucial factor in determining the load limit of alkaline water electrolysis (AWE) due to the risk of explosion with high HTO levels. In this study, we analysed the impact of circulating electrolytes, carrying dissolved gas, on HTO in a home-designed zero-gap alkaline water electrolysis system, operating at atmospheric pressure and constant temperature. By comparing the experimental results from mixed and separated cycles, we found that the amount of dissolved hydrogen in the electrolyte significantly contributes to HTO. We then developed a theoretical model to predict HTO values and experimentally confirmed a linear relationship between the HTO and the ratio of electrolyte circulation to gas production (Q L / Q O 2 ). Based on this evidence, we proposed a new electrolyte circulation control strategy that reduces the HTO value by as much as 63.56%. These findings could help overcome the load limit of alkaline water electrolysis systems, which is crucial for their large-scale application. [Display omitted] • Electrolyte circulation contributes significantly to HTO. • Circulating electrolytes carries dissolved hydrogen that increases HTO. • Optimization of electrolyte circulation helps to reduce HTO by up to 63.56%. [ABSTRACT FROM AUTHOR]

Atomically dispersed cerium species, anchored to high-area alumina by unsaturated penta-coordinated aluminum, strongly interact with atomically dispersed Cu species to provide active centers for water–gas shift reaction (WGSR). The alumina-anchored Ce3+ species stabilize atomically dispersed Cu+ to form Cu+–Ce3+ active complexes and they work synergistically to enhance low-temperature WGSR activity. This work offers alternative approaches to developing low-cost catalysts for the WGSR process. [ABSTRACT FROM AUTHOR]

Objective Oil and gas fields brine contains impurities such as petroleum and suspended solids, which have potential impacts on the adsorption and separation of lithium resources. This papper studies the feasibility of lithium adsorption extraction from gas field water and the adaptability of mainstream adsorbents in the market for lithium extraction. Methods The study compared the effects of pH and temperature on the adsorption and desorption efficiency of three types of powder adsorbents: aluminium-based, titanium-based, and manganese-based adsorbents. Aluminium-based adsorbent was selected, and the effects of adsorbent morphology, brine, and brine feed flow rate on adsorption and desorption efficiency were studied, and its cycling stability was evaluated. Results Under the optimal conditions, the saturated adsorption capacities of the three adsorbents are approximately 7.9 mg/g, 12.5 mg/g and 15.3 mg/g, respectively. In this experiment, the ratio of sodium to lithium and potassium to lithium in the desorption solution of aluminum adsorbent is better than that of titanium-based and manganese-based adsorbents, and the dissolution loss rate of titanium and manganese adsorbents is 20 and 70 times that of aluminum-based adsorbent, respectively. The service life during long-term operation is significantly shorter than that of aluminum series adsorbents. The ceramic membrane was used to remove suspended solids and petroleum from brine before the lithium extraction. Under the conditions of 20 BV of brine feed, 12 BV/h of brine feed flow rate, 10 BV of desorption water volume, and 10 BV/h of desorption flow rate, the adsorption capacity of aluminum molding adsorbent, as well as the concentration of lithium in tail brine remain stable in ten consecutive cycles of single-column experiments, with an average lithium adsorption rate of 79.2%. Conclusion It is feasible to use the adsorption method to extract lithium resources from the brine of Longwangmiao gas field. [ABSTRACT FROM AUTHOR]

An analytical solution of the problem of heating a composite spherical droplet consisting of a liquid hydrocarbon and a microdroplet of water in a hot gas flow is presented. A microdroplet of water is located in the center of a droplet of hydrocarbon. At the hydrocarbon–water interface, the conjugation conditions are specified; at the outer boundary of the hydrocarbon droplet — a condition of convective heat exchange. The unsteady temperature of a drop is represented by an analytical formula, which is an expansion of the solution in terms of eigenfunctions of the Sturm–Liouville problem. The eigenvalues are found numerically from the characteristic equation. A condition for the orthogonality of eigenfunctios in a composite droplet with discontinuous thermophysical properties is derived. The results of calculations using the obtained analytical formula are in satisfactory agreement with the experimental data. Erroneous methods are discussed in previously presented publications by other authors. [ABSTRACT FROM AUTHOR]

The paramount concerns of global warming, fossil fuel depletion, and energy crises have prompted the need of hydrocarbons productions via CO2 conversion. In order to achieve global carbon neutrality, much attention needs to be diverted towards CO2 management. Catalytic hydrogenation of CO2 is an exciting opportunity to curb the increasing CO2 and produce value‐added products. However, the comprehensive understanding of CO2 hydrogenation is still a matter of discussion due to its complex reaction mechanism and involvement of various species. This review comprehensively discusses three processes: reverse water gas shift (RWGS) reaction, modified Fischer Tropsch synthesis (MFTS), and methanol‐mediated route (MeOH) for CO2 hydrogenation to hydrocarbons. Along with analysing the reaction pathways, it is also very important to understand the real‐time evolvement of catalytic process and reaction intermediates by employing in‐situ characterization techniques under actual reaction conditions. Subsequently, in second part of this review, we provided a systematic analysis of advancements in in‐situ techniques aimed to monitor the evolution of catalysts during CO2 reduction process. The section also highlights the key components of in‐situ cells, their working principles, and applications in identifying reaction mechanisms for CO2 hydrogenation. Finally, by reviewing respective achievements in the field, we identify key gaps and present some future directions for CO2 hydrogenation and in‐situ studies. [ABSTRACT FROM AUTHOR]

The kinetics and equilibrium conditions of carbon dioxide hydrate formation in 'dry water" disperse system were studied using different types of hydrophobic silicon dioxide nanoparticles under isochoric conditions at 273.15 K temperature and 3 MPa initial pressure. Also studied was the effect of "dry water" on the kinetics of carbon dioxide hydrate dissociation under a pressure below the equilibrium and at 268.15 K temperature. [ABSTRACT FROM AUTHOR]

During Fuel Cell Vehicle (FCV) operation, the liquid water in gas diffusion media (GDM) prevents the reaction gas from reaching the reaction zone and lead to output power fluctuation and reduce the lifespan of FCV. In the present research, hydrophobicity gradient settings of micro-porous layer (MPL) and gas diffusion layer (GDL) are optimized to improve the water removal ability of GDM. Computational fluid dynamics (CFD) model is constructed for numerical simulations to analyze the fuel cell power output and the water content in the GDM with different hydrophobicity gradients. Experiments with different hydrophobicity gradients, which are specifically prepared with corresponding concentrations of polytetrafluoroethylene (PTFE) solutions, are conducted for validation of simulation results. It is shown that the positive hydrophobicity gradient of MPL and GDL provides a better capacity for water removal and oxygen transport. The contact angles of MPL and GDL are further optimized as 147.9°-138.6° by genetic algorithm integrated with the CFD simulations. [ABSTRACT FROM AUTHOR]

The pulsation of bubbles and the impact load from reverse flow, generated by the evolution of semiclosed initial intermittent bubble multiphase flow during underwater launches, are crucial factors affecting launch safety. This paper employs the mixture multiphase flow model and the interphase heat and mass transfer model to simulate the interaction between the gas inside a partially enclosed cylinder and the water medium outside the cylinder, combined with simulation and piggybacking experiments, to analyze the flow process and load state. The numerical model is further utilized to study the evolution of the multiphase flow field of the semienclosed initial intermittent bubble, the pulsating load of the bubble, the impact load of the inverted water flow, and the influence of structural dimensions on the load. The results show that the initial intermittent bubble in the mouth of the cylinder experiences an expansion–contraction–expansion pulsation process, and as the migration of the interface between the phases results in significant pressure pulsation, the peak pulsation can exceed twice the pressure difference between the initial gas pressure inside the cylinder and the hydrostatic pressure at the mouth of the cylinder. At the late stage of bubble pulsation, a large amount of water with pulsating bubbles flows into the semiclosed cylinder, and the pulsation-induced velocity and gravity are used to form a high-speed inverted water flow. The interaction between the inverted water and the gas inside the cylinder generates an oscillating shock load where the maximum shock load is significantly greater than the ambient pressure load. Additionally, the effect of structural dimensions on the load state under the same intermittent conditions is examined. [ABSTRACT FROM AUTHOR]

C4 NAD‐malic enzyme (NAD‐ME) species occurs in drier regions and exhibit different drought responses compared to C4 NADP‐malic enzyme (NADP‐ME) species. However, a physiological mechanism explaining the geographical discrepancies remains uncertain. This study examined gas exchange patterns that might explain different distributions observed between two subtypes of C4 photosynthesis. We measured the response of leaf gas exchange to vapour pressure deficit (VPD) and CO2 in plants from six distinct C4 clades having closely related NAD‐ME and NADP‐ME species using a Li‐Cor 6400 gas exchange system. We found that NAD‐ME species exhibited greater relative reductions in stomatal conductance with increases in VPD than NADP‐ME species but observed no consistent subtype differences in C4 cycle activity as indicated by the initial slope of the A response to intercellular CO2 concentration. Based on these results, we hypothesise the greater response of gs to increasing VPD may enable NAD‐ME plants to outperform NADP‐ME plants in hot, dry environments where VPD is normally high. Summary statement: NAD‐malic enzyme (NAD‐ME) C4 species have more sensitive stomatal closures in response to increasing vapour pressure deficit than NADP‐malic enzyme C4 species which may explain why NAD‐ME grass species are found in drier areas than NADP‐ME species. This provides insight into the role of plant eco‐physiology in shaping biogeography. [ABSTRACT FROM AUTHOR]

In order to clarify the water invasion law and residual gas distribution characteristics in edge and bottom water gas reservoirs with multi-well development, a large-scale three-dimensional physical simulation model was developed and a physical simulation experiment method for the water invasion law of multi-well development in sandstone gas reservoirs with strong water drives was established. Water invasion physical simulation experiments of multi-well development under the conditions of different water body multiples and production systems were conducted. The results show the following: (1) Gas wells near fractures and high-permeability zones experience the earliest water breakthrough. The larger the water body multiple, the faster the rate of water invasion, the earlier the water breakthrough time of gas wells, the more severe the degree of water invasion in gas reservoirs, and the lower the ultimate recovery rate. (2) Shutting in low-position gas wells immediately after water breakthrough reduces the overall water production of the gas reservoir and extends the overall water-free gas production period. However, the ultimate recovery rate is lower than when the wells are not shut in. (3) The residual gas in the fracture model is mainly distributed around the fracture and the edge of the gas reservoir, with the ultimate recovery rate ranging from 38.5% to 58.2%. The residual gas in the fracture–high-permeability zone model is mainly distributed around the fracture–high-permeability zone and the edge of the gas reservoir, with the ultimate recovery rate ranging from 28.32% to 41.8%. The experimental results have important guiding significance for the economical and efficient development of similar gas reservoirs. [ABSTRACT FROM AUTHOR]

Sample preparation is a key step in the analytical procedure. This step is a time- and labor-consuming process, and often it is also expensive, with costs being influenced by the consumption of materials and reagents. Additionally, the toxicity of the reagents, waste generation, and energy consumption affect the environment and the safety of the analyst. New trends in sample preparation are focused on the development of miniaturized methods that are consistent with the principles of green sample preparation and contribute to environmental sustainability. The results of a comprehensive assessment of ten methods of preparing water samples for the determination of UV filters using gas chromatography are presented. Three assessment tools were used for this purpose: AGREEprep (the analytical greenness metric for sample preparation), BAGI (the blue applicability grade index), and the RGB 12 algorithm (red–green–blue model). All the differences and similarities between the three aforementioned metrics are discussed in this manuscript. The results of the evaluation of the most frequently used microextraction methods show their ecological friendliness, effectiveness, and practicality. The results of this assessment will allow researchers to identify the strengths and weaknesses of the given methods and select those that meet their requirements. [ABSTRACT FROM AUTHOR]

The saturation of total dissolved gases (TDG) in water remains around 100%. Certain circumstances can lead to TDG values exceeding 100%, resulting in TDG supersaturation (TDGS). TDGS above about 110% can be toxic to animals that rely on water for gas exchange. However, saturation beyond 200% can occur in freshwater downstream of dams and hydroelectric power plants. Despite its impact, TDGS is often overlooked as a hazard to aquatic life, particularly for benthic macroinvertebrates. This study aimed to examine the effects of TDGS on nine species of benthic macroinvertebrates. We used replicated tank studies to manipulate TDGS levels from 100% to 120% and investigated the overall survival and species‐specific effects on survival and buoyancy. We also present a summary on the effects of TDGS on invertebrate species previously tested. The results indicate that seven of nine species exhibited increased buoyancy when exposed to TDGS, causing them to float on the water surface. Additionally, a Cox Proportional Hazards model revealed a significant effect of TDGS on the survival of the macroinvertebrates. The sensitivity towards TDGS varied greatly among species of benthic macroinvertebrates, and significant species‐specific effects were only observed for Isoperla grammatica, Baetis rhodani and Asellus aquaticus. Among these, the two latter species showed clear dose‐related effects caused by TDGS, enabling the assessment of LT50 (time required to kill half of the tested population). B. rhodani was most sensitive with a LT50 of 3.7 days at 119% TDGS. Both species had visible air bubbles under the exoskeleton. Our findings highlight that direct and indirect effects on benthic macroinvertebrates can occur even at low to moderate levels of gas supersaturation, likely causing reduced density, decreased species diversity and altered species composition. The emerging evidence strongly supports the implementation of regulations on TDGS in freshwaters. [ABSTRACT FROM AUTHOR]

The downstream processing of biocrudes obtained from direct biomass pyrolysis poses significant challenges due to stability issues, necessitating costly upgrading for further coprocessing with refinery feeds. This study examines the impact of torrefaction pretreatment on pyrolysis product distribution and biocrude composition using sawdust (SD) and groundnut shell (GS) feeds. Torrefaction was conducted at varying temperatures (200, 250 and 300°C) for 30 min under different reactor conditions. Increasing the severity of torrefaction resulted in decreased biocrude yields with reduced water content and gas formation, particularly evident with GS. A torrefaction temperature of 250°C and 30 min of pretreatment yielded higher phenolics and hydrocarbons. This increase in phenolics can be attributed to lignin enrichment during torrefaction, which, in the presence of a catalyst, undergoes deoxygenation leading to hydrocarbon formation. The influence of feed particle size, whether in powder or pellet form, on biocrude yield and composition was found to be minimal. Catalytic pyrolysis of SD using molecular sieve catalysts yielded the highest hydrocarbon (42%) and aromatic content (44%) at catalyst to biomass ratios of 1:1 and 2:3. The combination of torrefaction and pyrolysis was shown to enhance the quality of biocrude by increasing its hydrocarbon content, but at the expense of lower liquid yields. Experimental observations were supported by statistical analysis tools such as principal component analysis, which assessed pyrolysis product yields and composition. [ABSTRACT FROM AUTHOR]

To study the influence of various factors on coal permeability in the process of coal seam water injection and the relationship between water injection parameters, an experimental system of highly pressurized water invasion and gas seepage is developed. The system consists of four parts: an overburden pressure loading unit, a micro water injection control unit, a gas injection, and vacuum pumping unit, data acquisition and real-time monitoring unit. It can not only be used for coal seam water injection radial seepage experiments. It can also be used as a set of experimental systems to simulate the geothermal exploitation of deep coal seams and explore the heat transfer law of geothermal exploitation. To verify its applicability, a coal seam water injection seepage experiment is carried out based on the experimental system. The results show that the coal permeability increases by 7–31% before and after water injection; at the same time, under different stress conditions, the internal and external pressure difference of the coal sample before and after water injection has a decrease of 0.01–0.05 MPa. The conclusion is consistent with previous studies, which shows that the experimental system is accurate and reliable. [ABSTRACT FROM AUTHOR]

This novel research presents an investigation on petroleum products dehydration using the adsorption method by low-cost adsorbents. To investigate the performance of proposed process intended to separate emulsified water, synthetic stabilized water emulsions in different petroleum products (Gasoline, Kerosene, and Gas oil) which equal 300, 600, and 800 ppm were prepared. Afterwards, under batch conditions, natural zeolite and activated carbon as economic adsorbents were utilized for the dehydration process. The characteristics of adsorbent was examined using SEM and XRD analysis. The obtained results from BET analysis also depicted that the specific surface area of activated carbon was considerably more than that of zeolite. Results showed that both zeolites and activated carbon can effectively purify petroleum products from undesirable emulsified water. The comparison of the adsorbents' efficiency indicated that activated carbon has a higher affinity than zeolite for water in gasoline and gas oil, however, they had almost the same adsorption capacity in kerosene dehydration. The maximum water removal percentage of gas oil, kerosene and gasoline using zeolite was 84.84, 92.17, and 88.64, respectively. Dehydration by activated carbon also led to 86.44, 93.43 and 90.2 per cent water removal from gas oil, kerosene and gasoline, respectively. [ABSTRACT FROM AUTHOR]

Cleaning up carbon monoxide (CO) in water gas shift feedstocks is crucial for fuel cell applications. The catalytic transformation of CO in hydrogen-rich feeds poses a significant challenge in environmental catalysis. To address this issue, a range of Cu–Mn-based monometallic and bimetallic catalysts with diverse supports (such as alumina, silica, zirconia, and titania) were employed. Temperature programming techniques were utilised to observe the reduction and oxidation behaviours of these catalysts. The investigation involved testing CO oxidation at various temperatures over copper and manganese-based supported catalysts in the presence of H2O and CO2 (simulating realistic conditions). A positive impact of H2O on catalytic performance was noted, whereas CO2 had a suppressive effect. Furthermore, the specific support materials (Al2O3, SiO2, TiO2, and ZrO2) were studied to understand their roles in CO oxidation under realistic conditions. In the presence of water, alumina catalysts containing bimetallic metals (Cu–Mn) exhibited 100% CO conversion even at a lower temperature of 160 °C. Conversely, under the predominant influence of CO2, alumina catalyst (Cu–Mn) showed 55% CO conversion. The exceptional performance was attributed to CO preferential adsorption on highly active Cu–Mn sites and a small H2-oxidative atmosphere of the catalysts. The activity results highlighted the strong dependence of CO conversion on reaction temperatures, the presence of metals, and the types of supports. Overall, these findings suggest the potential use of these catalysts for H2 purification under realistic conditions. [ABSTRACT FROM AUTHOR]

The article presents the results of theoretical studies of the ignition process of a water-coal fuel particle under conditions of high-temperature heating at high pressures of the external environment. The authors have developed a new mathematical model of the water-coal fuel particles ignition under stress (pressure – Pg = 1–200 bar, and temperature Tg = 873–1273 K) heating conditions. The mathematical model differs from the known ones by a detailed description of the physicochemical processes occurring during the induction period of time, as well as the processes of phase transitions under high pressure conditions. Based on the results of numerical simulation of the ignition process, it was found that the pressure of the external environment (Pg) has a significant effect on the characteristics and conditions of ignition of water-coal fuel particles. It was shown that the tign(Pg) dependence is essentially nonmonotonic. The authors have established that when Pg changes in the range from 1 to 30 bar (for oxidizer temperatures (Tg = 873–1273 K), an increase in the ambient pressure leads to a nonmonotonic increase in tign. In this way such a dependence tign(Pg) is due to the joint influence of two significant parameters of the factor space, which significantly affects the dynamics of the thermal treatment of fuel. With an increase in the pressure of the mixture of oxidizer and combustible gases, the saturation temperature (the temperature of intense evaporation of water) increases, at the same time, the heat of the phase transition (QL) decreases and the rate of release of pyrolysis gases into the oxidizing environment decreases. Based on the results of the theoretical studies, it has been shown that for efficient combustion of water-coal fuel under the conditions of the combustion chambers of a GT at oxidizer temperatures Tg≥1073K, the pressure in the combustion chamber of the GT must be at least 50 bar. [ABSTRACT FROM AUTHOR]

The performance of ammonia hydrogen fuel cells (AHFCs) with the same activated area but different aspect ratio is quite different. In this paper, based on the diffusion characteristics of hydrogen nitrogen mixture, five different aspect ratios of AHFCs were designed, and the influence of aspect ratio on the performance of AHFCs was studied by combining experiment and simulation analysis. The results reveal that the power of AHFCs reaches the maximum when the aspect ratio is 1, that is, the shortest hypotenuse of the plate. With the extension of the hypotenuse, the output power decreases, and the output power decreases by 19.3% when the aspect ratio is 4. Due to the strong ability of hydrogen diffusion, when the aspect ratio of AHFCs is 4, the proportion of hydrogen and oxygen starvation area at the interface reaches the maximum and minimum, which are 11.8% and 0.3% respectively, which is contrary to the aspect ratio of 0.25. A larger aspect ratio is conducive to the uniform distribution of gas-water-heat. Although the AHFCs with aspect ratio of 0.64 has advantages in power generation efficiency and fuel utilization, the pressure drop loss increases by 43.7%, and the pressure drop loss with aspect ratio of 0.25 increases by 141.2%. • Experimental data of AHFCs with different aspect ratios are obtained. • Power generation efficiency of AHFCs with different aspect ratios is compared. • AHFC with the shortest hypotenuse has the largest output power. • CV is used to characterize the uniformity of gas-heat-water distribution in AHFC. [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]

In this paper, copper slag is used as the heat carrier of coal gasification reaction, and CaO is used as the CO 2 adsorbent of syngas to solve the problem of high cost of heat source and high proportion of CO 2 produced by coal gasification. When copper slag is used as the heat carrier, the adsorption effect of CaO on CO 2 is most pronounced at temperatures of 600 °C and 700 °C, with CO 2 proportion reduced to 8% and H 2 proportion reaching 65%. Additionally, CaO exhibits a significant promotion effect on carbon conversion rate and gasification efficiency at temperatures above 800 °C, with the maximum carbon conversion rate reaching 89% and the highest gasification efficiency reaching 78%. At low temperatures, CaO primarily functions in gas phase reaction, such as WGS reactions, hydrocarbon reforming reactions, tar reforming reactions, and pyrolysis reactions. As the temperature increases, CaO primarily functions in gas-solid reactions such as oxidation reactions and secondary water gas reactions. In high-temperature environments, iron compounds present in copper slag undergo iron reduction reactions, while the Ca 2 Fe 2 O 5 compound formed from the reaction of CaO and Fe significantly promotes reforming reactions. • The copper slag is used as the heat carrier, and the waste heat in the copper slag is utilized. • CaO was selected as the adsorbent, and the synergistic effect with copper slag was found during adsorption. • The proportion of H 2 in syngas can be increased to 89 %. • The reaction mechanism of different temperature stages was analyzed. [ABSTRACT FROM AUTHOR]

The global population's rapid growth, economic expansion, and ongoing urbanization have led to a significant surge in energy demand. Green hydrogen has found new interest in most scientific discussions because it is more environmentally friendly, scalable, and has wide application. However, it has general disadvantages, such as storage, pollutants, and generation costs. This review critically examined the current challenges of hydrogen production and how it can be further scaled down to attract biogas players and admirers. Several hydrogen production technologies were critiqued in line with user-friendliness and low energy requirements during production. The concept of 'biogas to hydrogen' and 'biomass to hydrogen' could potentially reduce the cost of green hydrogen production to about 40%. However, the main challenge of this concept is the wastage of feedstock and cost-effective hydrogen separation technologies. It was also observed that, unlike the thermochemical conversion, the biological conversion has a low energy requirement, further reducing the cost of production by 15%. The review observed that the 'biomass to biohydrogen,' which is becoming cheaper, is plagued with feedstock wastage and inefficient mechanisms to expunge impurities. It was concluded that the biological water gas shift reaction is expected to attract biogas users as its technique is similar procedurally. Hence, developing countries can now participate in cheap green hydrogen. [Display omitted] • Examined the major challenges of hydrogen production. • Evaluated the hydrogen production technique that is less cumbersome. • Highlighted ways hydrogen production can be accepted as biogas especially in developing countries. [ABSTRACT FROM AUTHOR]

Highlights: Challenges and future directions for 3D-printed metal-organic frameworks (MOFs) monoliths in environmental applications are discussed. Various strategies for fabrication of 3D-printed MOF monoliths are summarized. Advancements in 3D printing enable customizable and high-performance MOF monoliths. 3D orienting of MOFs opens avenues for applications in water treatment and gas adsorption. Metal–organic frameworks (MOFs) have been extensively considered as one of the most promising types of porous and crystalline organic–inorganic materials, thanks to their large specific surface area, high porosity, tailorable structures and compositions, diverse functionalities, and well-controlled pore/size distribution. However, most developed MOFs are in powder forms, which still have some technical challenges, including abrasion, dustiness, low packing densities, clogging, mass/heat transfer limitation, environmental pollution, and mechanical instability during the packing process, that restrict their applicability in industrial applications. Therefore, in recent years, attention has focused on techniques to convert MOF powders into macroscopic materials like beads, membranes, monoliths, gel/sponges, and nanofibers to overcome these challenges.Three-dimensional (3D) printing technology has achieved much interest because it can produce many high-resolution macroscopic frameworks with complex shapes and geometries from digital models. Therefore, this review summarizes the combination of different 3D printing strategies with MOFs and MOF-based materials for fabricating 3D-printed MOF monoliths and their environmental applications, emphasizing water treatment and gas adsorption/separation applications. Herein, the various strategies for the fabrication of 3D-printed MOF monoliths, such as direct ink writing, seed-assisted in-situ growth, coordination replication from solid precursors, matrix incorporation, selective laser sintering, and digital light processing, are described with the relevant examples. Finally, future directions and challenges of 3D-printed MOF monoliths are also presented to better plan future trajectories in the shaping of MOF materials with improved control over the structure, composition, and textural properties of 3D-printed MOF monoliths. [ABSTRACT FROM AUTHOR]