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CO 2 methanation has emerged as a promising strategy for the greenhouse gas CO 2 utilization and storage of hydrogen. However, achieving low temperature activity and high temperature stability remains challenging due to the sintering of Ni-based catalysts. To address these limitations, this study introduces a Ni–CaZrO 3 catalyst featuring a perovskite phase supported on ZrO 2 , prepared via citrate complexation and impregnation methods. In this approach, a perovskite-type oxide (PTO) of CaZrO 3 forms through a solid reaction on the surface of ZrO 2 with impregnated CaO. The formation of CaZrO 3 on Ni/ZrO 2 restrains the ZrO 2 support aggregation and reduces the particle size of Ni nanoparticles (NPs), thereby enhancing the activity for CO 2 methanation. The interaction between Ni–CaZrO 3 , and ZrO 2 effectively confines the Ni NPs and CaZrO 3 , enhancing the sintering resistance of Ni–CaZrO 3. This leads to excellent stability of the resulting catalyst for CO 2 methanation. The Ni–CaZrO 3 /ZrO 2 catalyst achieves 85% CO 2 conversion and maintains 100% methane selectivity at 300 °C, demonstrating the prolonged stability over 100 h at 550 °C. Notably, the loading of CaZrO 3 in a perovskite phase on ZrO 2 via solid surface reaction represents an interesting and valuable route, which could be extended to loading other PTOs for industrial applications. [Display omitted] • Ni and CaZrO 3 with perovskite phase loaded on ZrO 2 via solid surface reaction. • Perovskite-type CaZrO 3 reduced Ni particle size and enhanced surface area. • Improved interaction between Ni–CaZrO 3 and ZrO 2 compared to Ni and ZrO 2. • High Ni dispersion achieved 85% CO 2 conversion at 300 °C with 100% CH 4 selectivity. • Ni–CaZrO 3 confinement improved stability over 100 h at 550 °C and anti-sintering. [ABSTRACT FROM AUTHOR]

The autoignition of a stoichiometric hydrogen/air mixture laden with uniformly distributed coal char particles is simulated with the Eulerian-Lagrangian approach under isochoric conditions. A zero-dimensional model is adopted to assess the effects of gas temperature, pressure, particle diameter, and concentration on ignition dynamics. Increasing the initial temperature reduces the ignition time and maximum heat release rate of the homogeneous reactions, while the parameters for particle reactions stabilize after reaching a critical temperature. Initial pressure exhibits a non-monotonic influence on gas phase ignition, with higher pressures promoting particle autoignition. An increase in particle diameter decreases the ignition time for the homogeneous reaction, approaching that of particle-free conditions. Meanwhile, particle ignition time first decreases and then linearly increases. Increasing particle concentration reduces the interphase disparities of ignition times, while the two-phase ignition times rapidly rise after exceeding the critical concentration. Moreover, pre-ignition temperature equilibrium (PTE) significantly impacts the ignition parameters and processes. PTE results in a minimal ignition time disparity between the gas and particles, with coal char particles markedly influencing hydrogen ignition. Failure to reach PTE leads to significant two-phase ignition time differences, with negligible impact from the solid phase on gas phase ignition. The particle effect ratio, δ , is introduced to evaluate these effects. Notably, the evolution variations in ignition time and heat release rate are determined by the existence of the PTE under corresponding initial conditions. The findings of this study are crucial for developing strategies to mitigate explosion hazards and enhance the performance of detonation propulsion systems using hybrid fuels. • Autoignition of H 2 /air/coal particles mixture under elevated conditions is simulated. • The effects of initial conditions on two-phase ignition dynamics are discussed. • Pre-ignition temperature equilibrium between two phases markedly affects ignition. [ABSTRACT FROM AUTHOR]

The rational design of MgO nanomaterials with rich oxygen vacancies has garnered significant attention. However, the influence of oxygen vacancies and alkalinity on the generation and stability of active oxygen, particularly regarding the antibacterial activity of MgO nanomaterials, remains uncertain. In this work, the defective MgO nanoplates with adjustable oxygen vacancy and alkalinity were successfully designed by thermal treatment in different atmospheres (air, vacuum, and N 2). MgO nanoplates calcined in N 2 atmosphere exhibited superior antibacterial activity against Escherichia coli (ATCC 25922), reducing colony counts from 571.5 to 53.5 CFU/mL at 750 μg/mL compared with MgO nanoplates calcined in air. At a low concentration (100 μg/mL), MgO nanoplates calcined in N 2 atmosphere exhibited remarkable antibacterial performance, achieving a colony survival ratio of only 6.8 %. This enhanced performance was correlated with a higher oxygen vacancy (O A) content (51.3 %) in MgO nanoplates calcined in N 2 compared to those calcined in air (26.5 %). Advanced characterization techniques and alkalinity measurements revealed that calcination in a N 2 atmosphere promoted oxygen vacancy formation on the MgO surface, accelerated MgO surface hydrolysis owing to oxygen vacancies, and increased OH− production. Consequently, this process enhances the participation of adsorbed oxygen in surface reaction, leading to the increased generation and stability of active oxygen in an alkaline environment. These findings provide valuable insights into the design of oxygen vacancies and offer a potential approach for constructing highly antibacterial nanomaterials. Such materials could find applications in personal protection and public health. [ABSTRACT FROM AUTHOR]

Hydrogen (H 2) accumulation in confined areas can pose a threat to the structure's integrity in case of an undesired ignition. Therefore, mitigation measures are critical in preventing such devastating accidents. Passive Autocatalytic Recombiners (PARs) are defined as safety devices developed for preventing H 2 accumulation in confined environments. During PARs operation, the ambient oxygen (O 2) concentration decreases due to the H 2 reaction on the catalyst surface, possibly reaching oxygen-limited conditions. In this work, a 2D transient numerical model was validated against experiments conducted at low O 2 dilution ratios. After validation, the model was also verified by comparing the results with numerical simulations from literature. It was found that oxygen-limited conditions occurred due to low O 2 concentrations at the catalyst surface. At these conditions, H 2 was not entirely recombined, decreasing the PAR efficiency. This indicates that in case of a H 2 release in a confined space, oxygen-limited conditions would cause H 2 accumulation due to limited PAR operation, increasing the risk of an undesired ignition. • Hydrogen recombination under low O 2 conditions can affect the PAR performance. • Oxygen-limited conditions occurred due to low O 2 concentrations at the catalyst surface. • High air flow resulted in a low O 2 residence time at the catalyst surface. • A single step mechanism produced reliable results at low O 2 concentrations. [ABSTRACT FROM AUTHOR]

In this study, two-dimensional numerical simulations of oblique detonation waves (ODWs) under a flight altitude of 10 km were performed. Because of their high importance in a zero-carbon economy, ammonia and hydrogen are considered as the fuel for aircrafts. Six cases with various hydrogen addition ratios in the fuel mixture were considered to explore the effects of hydrogen addition on the ignition structure, surface instability and NO emission of ODWs. It was found that as the hydrogen addition ratio decreases, the ODWs become more difficult to initiate with increased ignition length, and more complicated multi-wave system emerges with a second oblique detonation wave (SODW). The oblique wave angle is rarely influenced by hydrogen addition ratio. Two types of reaction surfaces, i.e. "saw-tooth" and "key-stone", along with a series of transverse waves and vortices can be observed for the case with a hydrogen addition ratio of 20% by volume in the fuel mixture. The oscillation amplitude of the reaction zone length, which quantifies the surface instability, increases with decreasing hydrogen addition ratios. The mass fraction of NO is the highest in the case with a hydrogen addition ratio of 40%. NO concentration is higher in detonation compared to that in deflagration in all cases. The pathway analysis of NO indicates that the thermal NO is the primary contributor to NO production in the cases with high hydrogen addition ratios, while the HNO pathway becomes more significant in the cases with low hydrogen addition ratios. • 2D numerical simulation of ODWs under a flight altitude of 10 km using NH3/H2 were performed. • The initiation characteristics, surface instability and NO emission of ODWs were reported. • The effects of hydrogen addition on the structure and pollutant emission of ODWs were examined. [ABSTRACT FROM AUTHOR]

• A highly crystalline BiOBr (c-BiOBr) is synthesized by a two-step process. • A high crystallinity of c-BiOBr enhances the interaction of pollutant and [Bi 2 O 2 ]2+. • The adsorbed pollutant on c-BiOBr plays a role of molecular modification. • The molecular modification effect facilitates the direct pollutant oxidation. • The active electron transfer from pollutant promotes the generation of more O 2 •–. The adsorption of pollutants can not only promote the direct surface reaction, but also modify the catalyst itself to improve its photoelectric characteristics, which is rarely studied for water treatment with inorganic photocatalyst. A highly crystalline BiOBr (c-BiOBr) was synthesized by a two-step preparation process. Owing to the calcination, the highly crystalline enhanced the interface interaction between pollutant and c-BiOBr. The complex of organic pollutant and [Bi 2 O 2 ]2+ could promote the active electron transfer from the adsorbed pollutant to c-BiOBr for the direct pollutant degradation by holes (h+). Moreover, the pollutant adsorption actually modified c-BiOBr and promoted more unpaired electrons, which would coupling with the photoexcitation to promote generate more O 2 •–. The molecular modification effect derived from pollutant adsorption significantly improved the removal of pollutants. This work strongly deepens the understanding of the molecular modification effect from the pollutant adsorption and develops a novel and efficient approach for water treatment. [ABSTRACT FROM AUTHOR]

The successful deployment of efficient oxygen evolution reaction (OER) electrocatalysts is highly essential for multiple clean-energy-related conversion technologies. Perovskite oxides, with compositional diversity and elemental complexity, are a classic kind of OER electrocatalysts, whereas their activity remains insufficient under the traditional adsorbate evolution mechanism (AEM) due to limited scaling relations. Herein, taking the Ba 0.5 Sr 0.5 Co 0.8 Fe 0.2 O 3-δ (BSCF) perovskite as a model system, we find a less Ru substitution strategy to boost the lattice oxygen reactivity for improved OER. The OER behavior of BSCF is greatly ameliorated as Ru doping reaches an optimal level (BSCFR0.1), delivering a lowered overpotential by 45 mV at 10 mA cm−2. Notably, such doping remarkably triggers the generation of more surface oxygen vacancies, promotes internal charge transfer, and enlarges the surface hydrophilicity, hence facilitating more lattice oxygen to participate in the surface reaction. These results demonstrate the feasibility of Ru incorporation for ameliorating the OER behavior of perovskites, and such strategy can be further leveraged to design other remarkable perovskite-based OER catalytic materials. • The Ru-doped BSCF series is synthesized by a simple solid-state reaction approach. • The OER behavior is greatly ameliorated as Ru doping reaches an optimal level. • Ru doping can trigger more oxygen vacancies, increase Co–O covalency, and enlarge the surface hydrophilicity. • Such doping also facilitates more lattice oxygen to participate in the surface reaction. [ABSTRACT FROM AUTHOR]

Numerical modeling of the high-speed flow of a multicomponent dissociated gas around a blunt body was carried out for the flow regime corresponding to the thermally stressed point of the gliding trajectory of entry into the Earth's atmosphere in the surface temperature range of 800–2000 K. As boundary conditions, a stage-by-stage model of heterogeneous catalysis of the interaction of dissociated air with the thermal protection material SiO 2 was used, previously developed by the authors on the basis of transition state theory and quantum mechanical calculations. The dependence of the modes of heterogeneous chemical reactions on the surface temperature and the density of surface adsorption centers and their influence on the chemical composition of the shock layer and the convective heat flux to the streamlined surface are analyzed. The contributions of individual mechanisms of heterogeneous recombination to the total rate of formation of molecules on the surface are estimated. The possibility of using the density of adsorption sites as an effective parameter when setting boundary conditions on a real thermal protection surface in flow problems is shown. • The influence of heterogeneous processes on the structure and chemical composition of the shock layer was studied. • The contribution to surface recombination of different mechanisms of heterogeneous catalysis was analyzed. • A significant influence of the number of adsorption sites on the regime of surface reactions has been shown. [ABSTRACT FROM AUTHOR]

Photoelectrochemical (PEC) performance of photoanode is limited by the cascade-dynamic processes, mainly including light absorption, charge separation, and surface reaction. This work adopted a strategy of nanocones modification on FTO substrate (FTO-NC) to enhance light utilization and photoelectrons collection for improved PEC water splitting. Comparative studies showed that FTO-NC enhanced the light scattering, promoting the conversion process of photon to electron/hole and enlarging the effective surface area of BiVO 4 for surface reaction. Meanwhile, cooperative Mo-doping and Co-MOF decoration improved the bulk electron transportation in BiVO 4 , hole migration towards the electrode surface, and accelerated the water oxidation reaction of photogenerated holes. The photocurrent density of FTO-NC/BiVO 4 -Mo/MOFs reached 3.56 mA cm−2, 6.14 times that of pristine BiVO 4. The IPCE of FTO-NC/BiVO 4 -Mo/MOFs photoanode achieve 60% at 1.23 V vs. RHE, demonstrating a significantly enhanced light utilization performance. This work presents new insight into boosting cascade-dynamic processes through collaborative strategies for highly efficient PEC water-splitting. [Display omitted] • FTO-NC had high light scattering effect for increasing light absorption of BiVO 4. • The photocurrent of FTO-NC/BiVO 4 -Mo/MOFs was increased by 6.14 times than FTO-BiVO 4. • FTO-NC/BiVO 4 -Mo/MOFs showed 2.7-times higher η transfer than FTO-BiVO 4. [ABSTRACT FROM AUTHOR]

Low carrier separation efficiency and slow surface reaction kinetics are the main factors for restricting the development of photocatalytic technology. Construction of double Z - scheme heterojunction and deposition of cocatalyst on semiconductor are considered to be effective strategies to solve these problems. However, it is challenging to integrate dual Z-scheme heterojunction and cocatalyst in one system to enhance photocatalytic activity. In our paper, a novel ternary heterostructure TiO 2 /g-C 3 N 4 /NiCoP (TCNNCP) photocatalyst was constructed by depositing NiCoP cocatalyst on three-dimensional spherical TiO 2 /g-C 3 N 4 surface. NiCoP in the composite can not only promote the surface reaction kinetics by reducing overpotential as a cocatalyst, but also improve the photogenerated carrier separation efficiency by constructing double Z-scheme heterojunctions with TiO 2 and g-C 3 N 4 as semiconductors. As a result, the optimized TCNNCP-2 composite exhibited a significantly improved photocatalytic hydrogen production activity of 2305.5 μmol g−1, which was 20.21 times higher than that of pure TiO 2 and 3.10 times higher than that of binary TiO 2 /g-C 3 N 4 composite. Additionally, TCNNCP-2 demonstrated excellent photocatalytic activity with an 86.2% removal rate for Cr(VI) within 2 h. These outstanding results can be attributed to the synergistic effect achieved through the construction of double Z-scheme heterojunctions and loading NiCoP cocatalyst, which enhance light-harvesting capability, carrier separation and transmission efficiency while promoting surface photocatalytic reactions. This research will contribute to the development of more bifunctional noble metal-free cocatalysts for efficient photocatalysis. [Display omitted] • A novel TiO 2 /g-C 3 N 4 /NiCoP photocatalyst was fabricated by depositing NiCoP cocatalyst on the surface of TiO 2 /g-C 3 N 4. • The TiO 2 /g-C 3 N 4 /NiCoP composite exhibited excellent photocatalytic activity for H 2 evolution and Cr(VI) reduction. • Integration of dual Z-scheme heterojunction and cocatalyst in one system improves photocatalytic activity. • Photocatalytic mechanism and the role of NiCoP in TiO 2 /g-C 3 N 4 /NiCoP ternary heterojunction were investigated in detail. [ABSTRACT FROM AUTHOR]

Zeolitic Imidazolate Framework-8 (ZIF-8) material was prepared by chemical precipitation method. The microstructure and physical properties of the as-prepared samples were characterized by XRD, BET, FESEM and UV spectrophotometer. The self-made four-channel measurement device was used to test the gas sensitivity of ZIF-8 material toward ethanol gas under photo-thermal synergistic excitation. The results showed that the sample was typical ZIF-8 (E g = 4.96 eV) with a regular dodecahedron shape and the specific surface is up to 1793 m2/g. The as-prepared ZIF-8 has a gas response value of 55.04 to 100 ppm ethanol at 75°C and it shows good gas sensing selectivity and repeated stability. The excellent gas sensitivity can be attributed to the increase of free electron concentration in the ZIF-8 conduction band by photo-thermal synergistic excitation, and the large specific surface area of ZIF-8 material provides more active sites for gas-solid surface reaction. The reaction mechanism of ZIF-8 material under multi-field excitation was also discussed. [Display omitted] [ABSTRACT FROM AUTHOR]

The widespread production and use of hydrogen (H 2) requires safe handling due to its wide range of flammability and low ignition energy. In confined and semi-confined areas, a H 2 leak creates potential for accumulation of flammable gases. A Passive Autocatalytic Recombiner (PAR) is a safety device for preventing H 2 accumulation. PAR is equipped with catalyst plates that assist the activation of the H 2 recombination with oxygen (O 2) at low concentrations. The heat released from the reaction decreases the gas density, creating a self-sustained natural convective flow, continuously supplying the catalyst surface with H 2 present in the air surrounding the PAR. In this study, a 2D numerical model is developed to simulate PAR operation. The model is used to analyze surface reactions, forced versus natural convective flow, plate spacing, heat losses, hydrogen recombination rates, carbon monoxide (CO) poisoning and their influence on the catalyst performance. Experimental data are used for model calibration and validation, showing good agreement for different conditions. The model shows that H 2 is almost entirely recombined whereas CO is only partially recombined. Natural and forced convection flows result in similar velocity profiles and large plate spacing produces higher temperatures, higher velocities but lower H 2 conversion. Moreover, the model shows a new feature for simulating CO poisoning via surface reactions. Overall, the model provided novel insights into PAR operation, showing the importance of surface reactions and it will be useful to assess design aspects and the effectiveness of PARs for H 2 mitigation. • A new CFD model to simulate Passive Autocatalytic Recombiners was developed. • The model was validated with published experimental results. • Hydrogen and carbon monoxide recombination was simulated via surface reactions. • Catalyst poisoning was simulated and inhibited the hydrogen recombination reaction. [ABSTRACT FROM AUTHOR]

As a main component of alkenes, 1-octene is the key important intermediate in the process of oxidation or pyrolysis of n-decane or higher alkanes. In this work, quantum chemistry calculations of the 1-octene combustion and pyrolysis were illustrated for the potential energy surface, including the H-abstraction reactions and subsequent isomerization and β -dissociation reactions. The primary β -dissociation reactions after the H-abstraction reaction involving H atoms and CH 3 /NH 2 /NO 2 radicals are detailed description with kinetic calculation. The rate constants of the primary pyrolysis reaction of 1-octene from 300 to 2000K were determined with the RRKM theory combined with CTST. The results indicated the H-abstraction reactions adhere to the Evans-Polanyi principle within the calculation uncertainty 1 kcal/mol. The 3-site exhibited the highest competitiveness in the 1-octene H-abstraction process and dominated, whereas the 1-site is lack of competitiveness due to overcome higher energy barriers (2–4 kcal/mol). The five-membered or six-membered ring in the H atom transfer process served as the most favorable structure for the isomerization reaction of 1-octenyl because of the lowest transition state energy. The dissociation channel for converting 1-octenyl to various octadienes and H atoms consumed the least 1-octenyl in the dissociation process. Following temperatures exceeding 570K, INT6 exhibits a preeminent 1-octenyl consumption ratio, attributed to the synergy between the enthalpy and entropy effects. The modified kinetic data of 1-octene H-abstraction reactions by four radicals and the subsequent isomerization and β -dissociation was expanded from 300 to 2000K, 0.01–100 atm. The modified model shows the better experimental prediction capabilities. • The potential energy surface and the dehydrogenation reaction rate of eight sites of 1-octene were calculated. • The potential energy surface and reaction rate of octenyl radicals isomerization were calculated. • The potential energy surface and reaction rate of the dissociation reaction of octenyl radicals were calculated. [ABSTRACT FROM AUTHOR]

Surface reactions underpin our collective understanding of mineral dissolution. This impacts a range of predictive geochemical models (for weathering, the fate and transport of metals) as well as industrial utilization of minerals. Yet atomistic details are rarely known due to the complex mineral/fluid interfacial environment. There is significant need to understand the mechanistic details of dissolution reactions and how they depend on surface morphology and solution conditions. This work utilizes surface pit models in conjunction with changes to solution composition that mimic pH to explore surface detachment of aluminate from gibbsite, which is a primary source of Al in soils and within the industrial processing of aluminum. Ab initio molecular dynamics simulations with enhanced sampling has been used to explore the detailed process of the detachment, the results of which indicate two potential pathways that are differentiated based upon the extent of water hydration. The heights of the energy barriers depend upon the local morphology which influence the number of bridges (quasi-)simultaneously broken (1 or 2) or the Al-O coordination of the neighboring aluminum atoms (5 or 6) at the armchair edge. pH effects are significant, with a nearly 50% reduction in barrier height under alkaline conditions that are relevant to geothermal fluids and Al extraction from minerals. [ABSTRACT FROM AUTHOR]

In the work, an improvement strategy for surface covering the quaternary layered oxide LiNi 0.90 Co 0.04 Mn 0.03 Al 0.03 O 2 with the ionic conductor (Li 3 BO 3) and electronic conductor (polypyrrole) is put forward to relieve the interface troubles and ameliorate the electrochemical properties of Ni-rich cathode. Benefiting from the multiple advantages of the double conductors, surface residual alkali and cation mixing of LiNi 0.90 Co 0.04 Mn 0.03 Al 0.03 O 2 are remarkably decreased, as well as the surface side reactions, which are helpful to enhance the interfacial and crystal structure stability during long-term working. As a result, the PPy-LBO coated cathode delivers the large discharge capacity of 149.5 mA h g−1 with 10.0C high rate, outstanding capacity of 167.5 mA h g−1 with −30 °C discharging, and prominent cyclic stability with 90.5 % capacity conservation rate after 200 cycles at 1.0C with 45 °C. Meanwhile, the full batteries prepared with PPy-LBO coated sample also demonstrate the brilliant performance including the safety capability (Nail penetration, Overcharging and Impact test) and long-term cycling when compared to the pristine cathode. [ABSTRACT FROM AUTHOR]

The high chemical inertness of silicon carbide (SiC) makes it difficult for surface chemical reactions to occur. Surface oxidation reactions are crucial for improving the processing efficiency and surface quality of SiC wafers. Extensive research has been conducted on conventional aqueous polishing slurries, while investigations on non-aqueous solvent-based polishing slurries have emerged as alternative options for enhancing SiC surface processing, as evidenced by recent scholarly reports. However, the surface chemical reaction mechanism of silicon carbide in either water or other hydroxyl groups containing solvents remains still unclear and is not well understood. In this work, ReaxFF molecular dynamics simulation was used to study the dynamic reaction processes between solvents and 6H SiC (001) surfaces. The oxidation of SiC surface in water and alcohol solvent is found to go through three stages: in the first stage, the solvent molecules move towards the SiC surface and react with the uncoordinated Si atoms and C atoms on the surface; in the second stage, the solvent molecules adsorbed on the surface of SiC reduces the Si –C bonding energy and promotes the breaking of Si –C bonds; in the third final stage, the migration of OH and H on the SiC surface induces the formation of Si – O –Si bonds, which promotes the continuous oxidation of the SiC surface. The order of simulated chemical reactivity between solvent and silicon carbide surface is consistent with experimental polishing removal rates. The reaction mechanism of solvent on silicon carbide surface was proposed by combining ReaxFF simulation results with polishing experiments, AFM, and XPS data analysis, shedding new insights on better understanding the mechanism of SiC chemical mechanical polishing. [ABSTRACT FROM AUTHOR]

Molten catalytic media are increasingly attracting interest as a suitable reaction environment where cracking of hydrocarbons and separation of the solid carbon product can be achieved simultaneously, ideally avoiding catalyst regeneration. In conditions relevant to industrial production, multiscale approaches are needed to predict the reactor performance, where the macroscopic dynamics of two-phase flow is combined with the evolution of the reaction inside individual bubbles. We here develop a thermodynamically-consistent, analytically solvable model for predicting the effective reaction rate resulting from the interplay between diffusive transport within the bubble and the surface reaction at the gas/liquid interface. The analytical solution is based on a spectral (eigenvalue/eigenfunction) expansion of the concentration profiles. We show how in practically affordable conditions, the effective characteristic time of the reaction can be estimated based only on the dominant eigenvalue of the diffusion-reaction problem. The closed-form knowledge of the dominant eigenvalue provides key insight in establishing the range of existence of diffusion-limited, mixed, and kinetics-controlled regimes. Based on the limiting solutions of the model, an approximate model for the conversion, yielding the explicit dependence of conversion on the equilibrium, kinetics and transport parameters is derived. The approach proposed is validated by comparing its predictions with the solution of the fully-coupled mass/momentum local balance equations obtained through a finite-element commercial solver enforced on a moving boundary domain to account for the bubble expansion due to the increasing number of moles in the gas phase. • Analytical solution proposed for conversion of a CH 4 bubble undergoing cracking. • Analytical model validated against mass/momentum coupled 2D model. • Transition between kinetics and diffusion-controlled regime established. • Relevant information captured by dependence of dominant eigenvalue on Da. [ABSTRACT FROM AUTHOR]

Titanium dioxide with suitable band edges is one of promising photocatalysts for water splitting. Nanotubes with one-dimensional structure can induce efficient charge transfers and hollow centers can provide large surface area for surface reactions. Modifying Ti foils for anodization can enhance light utilization of TiO 2 nanotube photoelectrodes. In this work, it is firstly to fabricate TiO 2 nanotube photoelectrodes on acid-etched Ti foils by anodization (MNT) for photoelectrochemical catalyzing water splitting. Different acid-etching durations are applied on Ti foils to induce various rugged surfaces. The resulting photoelectrodes present largely enhanced light utilization than that fabricated by the pristine Ti foil. The anodization duration is also optimized to find suitable lengths of MNT. The smallest overpotential of 524.7 mV at 10 mA/cm2 and Tafel slope of 167 mV/dec are obtained for the optimal MNT photoelectrode. The TiO 2 nanotubes grown on the pristine Ti foil shows the overpotential of 679.3 mV at 10 mA/cm2 and Tafel slope of 285 mV/dec. This result opens a blueprint for raising the photocatalytic ability by simply modifying the surface property of the conductive substrate. Other modifications may be applicable to enhance the roughness of Ti foils for growing more efficient MNT array as photocatalysis of water splitting. [Display omitted] • TiO 2 nanotube photoelectrodes are fabricated on acid-etched Ti foils by anodization. • Different acid-etching duration is used on Ti foil to induce various rugged surface. • Anodization duration is optimized to find the suitable lengths of TiO 2 nanotubes. • Smaller overpotential of 524.7 mV at 10 mA/cm2 and Tafel slope of 167 mV/dec are got. • High light absorbance and small charge transfer resistance are got for modified tube. [ABSTRACT FROM AUTHOR]

Poor conductivity and low catalytic activity of NiFe layered double hydroxide (LDH) limit its application as an electrocatalyst for oxygen evolution reaction (OER). In this work, heterostructure along with oxygen vacancy and amorphous structure, which is available to the enhancement of catalytic activity were introduced in the surface of NiFe-LDH by Co and W codoping using hydrothermal method. The overpotential of OER at 50 mA cm−2 is decreased from 304 mV of NiFe-LDH to 263 mV of W 0.5 Co 0.5 @NiFe-LDH. Moreover, the existence of W6+ species in LDH can significantly improve the electrochemical kinetics of OER as well as the stability of catalyst. This work provides a new strategy to induce active sites in the surface as well as inhibit the formation of defects in the bulk so as to enhance the catalytic activity and still maintain the stability nature of catalysts. Oxygen defects and amorphous structure are introduced by Co and W codoping in the surface of NiFe-LDH using hydrothermal method, which is available to enhance the catalytic performance for OER. [Display omitted] • Co and W elements are successfully co-dopped in the surface of NiFe-LDH by hydrothermal method. • Oxygen vacancies and amorphous structure are generated in NiFe-LDH by CoW surface codoping. • Multiple phase heterostructure in NiFeCoW-LDH enhances the oxidation ability of active sites. • The optimized W 0.5 Co 0.5 @NiFe-LDH presents a low overpotential of 263 mV at 50 mA cm−2 for OER. [ABSTRACT FROM AUTHOR]

Conversion of producer gas tar without coke generation is a great challenge. This study investigates conversion of tar model benzene using different configurations of highly non-porous ɣ-Al 2 O 3 packed bed reactor at 1000–1100 0C. The configurations comprised of different positions (relative to top (P 1), center (P 2) and bottom (P 3) of reactor furnace), heights (5, 13 and 25 cm) and particles sizes (0.5, 3 and 5 mm) of alumina packed bed. Steam and CO 2 were used as reforming media for tested benzene concentrations (0.4–1.8 vol%). The results showed benzene conversions of 48–91% with negligible steady thin coke generation using a packed bed (height: 25 cm, particles size: 3 mm) at P 1. Whereas, relative high benzene conversions of 63–93 and 68–95% at P 2 and P 3 respectively with unsteady thick coke generation at benzene concentrations greater than 0.4 vol% increased differential upstream pressures (DUPs) of beds. Similar unsteady coke generation at benzene concentrations greater than 0.8 vol% and temperature of 1100 0C was observed with packed beds of heights of 5 and 13 cm, and particles size of 0.5 mm at P 1. Generation of unsteady coke with condensed structure as evidenced by its characterization was attributable to increased benzene polymerization and reduced bed surface gasification reactions due to improperly installed packed bed. Developed kinetic model predicted well the generated coke. As conclusion, properly installed alumina packed bed pertaining to tar concentration and other experimental conditions may inhibit coke generation during tar conversion. • Packed bed position influenced both benzene conversion and observed coke generation. • Packed bed height and particles size influenced coke generation only. • Increased polymerization and reduced gasification reactions lead coke generation. • Reduced concentrations of steam other than of CO2 generated coke. • Developed kinetic model estimated the generated coke well. [ABSTRACT FROM AUTHOR]

The yttrium aluminium garnet (YAG) and sapphire materials are commonly used in laser and optical devices. Producing an ultra-precise surface quality is necessary for the application in optical devices. However, YAG and sapphire materials belong to difficult-to-machine materials with high brittleness and hardness. Therefore, ensuring the main criterion of producing a quality surface in the nanometre form with the ability to remove the material when finishing this material is challenging. Eliminating machining residues using chemical–mechanical slurry (CMS) is essential in creating ultra-precise components in optical devices. Based on this feature, this work investigates the efficiency of the CMS polishing process by comparing the surface reaction modes with the ionic and solid reaction modes when polishing YAG and sapphire materials. The study procedures aim to clarify the polishing performance corresponding to these two reaction types. Experimental analyses show the balance between CMS polishing technology's mechanical and chemical effects with the ionic reaction model that can be generated. Results also show that the ionic surface reaction modes give more uniform material removal than the solid reaction on YAG and sapphire crystal surfaces. Therefore, when polished by CMS technology with ionic surface reaction modes, the surface quality is better than solid reaction. In the CMS polishing with ionic responses, adding more Na 2 SiO 3 –5H 2 O content to the CMS is necessary if the chemical reaction is weak. This process will facilitate the –Si–OH components to be more distributed on the workpiece's surface, thereby improving reaction speed and correcting the balance between mechanical and chemical in polishing by CMS. This balance action results in an ultra-smooth YAG crystal surface without scratches, with a roughness obtained in the nanometre form (Ra = 1.031 nm) after polishing by CMS-2. [ABSTRACT FROM AUTHOR]

Symmetric solid oxide electrolysis cells (SSOECs) have attracted considerable interest because of their low fabrication cost and few compatibility issues. However, the development of SSOECs is restricted by the lack of electrode materials with desirable catalytic activity and stability. Herein, novel double-perovskite Sr 2 Ti 1−x FeNi x O 6 (STFNx) oxides are prepared and evaluated as electrodes for CO 2 electrolysis in SSOECs. The Sr 2 Ti 0.9 FeNi 0.1 O 6 (STFNi01) electrode shows the best performance with the minimum polarization resistance. The physicochemical characterization reveals that Ni substitution increases the concentrations of surface-adsorbed oxygen species and electrical conductivity and enhances CO 2 chemical adsorption, improving the electrode surface reaction kinetics, as evidenced by the distribution of relaxation time analysis. The STFNi01 symmetric cell presents a current density of 0.91 A cm−2 at 1.6 V and 800 °C and shows no performance degradation in the durability test due to the excellent carbon deposition resistance, indicating that STFNi01 is a promising electrode material for SSOECs. [ABSTRACT FROM AUTHOR]

In this work, the influences of polymers (HPMC E3, PEG 6000, PVP K25, PVP K30), temperature, stirring speed and polymer mass fraction on the oxaprozin (OXA) dissolution profiles were measured by a United States Pharmacopeia (USP) Ⅱ dissolution apparatus. The two-step chemical potential gradient model combined with the interfacial steady-state mass transfer model as well as PC-SAFT (perturbed-chain statistical associating fluid theory) were used to analyze the dissolution mechanism of OXA under different conditions. The presence of polymer could promote the surface reaction of OXA while temperature and stirring speed have different influences on the surface reaction and diffusion. The diffusion boundary layer thickness δ of OXA tablets increases with the increase of temperature and decreases with the increase of stirring speed. Based on the obtained surface reaction rate constant k s and diffusion rate constant k d , the dissolution profiles with high accuracy compared with the experimental data. [Display omitted] • Calculating the concentration at solid-liquid interface by mass transfer model. • The presence of excipients affects the solubility and dissolution mechanism. • Temperature and stirring speed affect the dissolution mechanism. • Surface reaction and diffusion work together to control dissolution. [ABSTRACT FROM AUTHOR]

Struvite (MgNH 4 PO 4 ·6 H 2 O，MAP), a type of high-quality, slow-release fertilizer, is the main component of urinary stones in animals and humans and causes scale formation in industrial pipes. Therefore, MAP dissolution is an important research topic. Herein, MAP dissolution experiments are performed and a thermodynamic model is developed to evaluate the influences of pH, temperature (T), and particle size (P s) on surface reaction resistance (1/k s) and diffusion resistance (1/k d). The results show that MAP solubility decreases with an increase in pH and the effects of pH change are more obvious than those of T or P s. The total resistance (1/k T) of MAP dissolution increases with pH increase, P s growth, or T reduction. The comparison of 1/k s and 1/k d reveals surface reaction as the MAP dissolution control step and indicates a linear relation among 1/k s , 1/k d , and the natural logarithm of P s at pH 7.0. [Display omitted] • The solubility of struvite is more affected by pH than temperature and particle size. • The resistances during the dissolution process of struvite were calculated. • Surface reaction is the controlling step in the dissolution of struvite. • The resistance was found to have a linear relationship with particle size at pH 7. [ABSTRACT FROM AUTHOR]

• NO 3 –, SO 4 2–, and WSON in coarse particles indicate heterogeneous conversion. • Excessive biomass burning led to an increase in coarse fractions of WSOC in PM 10. • Light absorption of aerosol extracts in water depends on aerosol size. • Coarse PM is a mixture of combustion particles and surface reactions with dust. To understand the differences in the composition and sources of PM 2.5 and PM 10 caused by coarse particles, integrated PM 2.5 and PM 10 samples were synchronously collected in Nanjing, East China, in summer 2020 and winter 2020/2021. Bulk and molecular speciation and light absorption measurements of aerosol extracts were performed, followed by positive matrix factorization (PMF) based on the PM 2.5 and PM 10 data sets, respectively. The difference in average concentrations of total bulk species between PM 2.5 and PM 10 was mainly caused by the distribution of considerable NO 3 –, SO 4 2–, Ca2+, and organic carbon (OC) in coarse particles. Coarse PM influenced by abrasion products from tire wear and leaves contributed about half of the low-volatility n- alkanes in summer. The contribution of coarse PM to biomass burning tracers and water-soluble OC increased in winter when biomass combustion was excessively active. More than 70% of sugar polyols were attributable to coarse PM in summer, and biomass burning could be an important source in winter. The light-absorbing organic chromophores were almost entirely associated with PM 2.5 , but water-soluble organic carbon (WSOC) exhibited stronger light absorption in PM 10 extracts than in PM 2.5 extracts possibly due to the influence of coarse PM on pH. PMF analysis indicated that biomass burning, aqueous-phase reactions, and processed dust were the main contributors of organic matter and its light absorption in winter. Biogenic primary and secondary sources made discernable contributions only in summer. The differences between PM 2.5 and PM 10 were likely attributed to mixing of crustal dust, combustion particles, and surface reactions. [Display omitted] [ABSTRACT FROM AUTHOR]

In order to investigate the effects of gas mixture components on the combustion characteristics of rotating detonation wave, two-dimensional simulation is presented to simulate the propagation process of rotating detonation wave with different methane conversions. The results indicate that there are five propagation modes of rotating detonation wave with different components: single-wave mode, single wave with counter-rotating components mode, double-waves mode, triple-waves mode and quadruple-waves mode. The detonation wave propagates along the forward direction in all five modes. With the increase of methane conversion, multi-wave mode appears in the combustion chamber. The fuel component has a great influence on the heat release ratio of detonation combustion. The velocity of detonation wave decreases with the increase of methane conversion. With the increase of methane conversion, the chemical reaction rate gradually increases, which leads to the intensification of chemical reaction on the deflagration surface. The reaction on the deflagration surface develops to the unburned fuel zone, which eventually leads to the formation of compression waves and shock waves in the fuel refill zone. When the shock wave sweeps through the fresh premixed gas, the reactant is compressed to form a detonation point and then ignite the fuel. A new detonation wave is finally formed. The total pressure ratio decreases with the increasing methane conversion, and the uniformity of the total pressure of outlet decreases with increasing methane conversion. • Component change of multicomponent mixture dictate propagation mode. • The influence of component change on detonation wave velocity and pressure is revealed. • The effect of deflagration surface reaction on the characteristics of detonation wave is analyzed. • Pressure ratio of combustion chamber with mixture of different components is compared. [ABSTRACT FROM AUTHOR]

Some seriously weathered jades of Fubin culture were unearthed at the Moyishan site in Lingnan, South China. These long-buried jades have many secondary changes such as discoloration, microstructural change and chemical composition variation. To explore the formation mechanism of secondary changes, the microstructure, mineral components, and chemical content of the jade samples and their buried soil are analyzed separately. The jade with red-brown shell is preserved well and shows better structural stability, further research indicates that it's the result of surface complexation reactions. During the long-term burial in acidic soil environment, the jade wrapped in the negatively charged kaolinite which absorbed Fe3+ to complexed on the jade surface. Iron(ⅲ) precipitates causes the dense shell to appear red-brown. [ABSTRACT FROM AUTHOR]

A large amount of spent MgO–C refractory is generated in steel plant every year. Because of the similarities in chemical and mineralogical composition of slag formers and MgO–C refractory, it is possible to reuse the spent MgO–C refractory as a steelmaking flux. To achieve this goal, it should promote the dissolution of MgO–C refractory during slag forming. In this study, the effect of slag composition on the dissolution behavior of spent MgO–C refractory in the CaO–SiO 2 –FeO slag system and the dissolution kinetics were investigated. It showed that the dissolution rate of MgO–C refractory was controlled by surface chemical reaction. The dissolution of MgO–C refractory led to an increase in the MgO content in slag while the FeO content decreased because the graphite in refractory was oxidized by FeO. Increasing temperature significantly promoted the dissolution of MgO–C refractory. The MgO–C refractory was readily dissolved in the low-basicity slag. A higher FeO content in slag was beneficial for the oxidation of graphite in refractory, resulting in better dissolution. The dissolution thickness of MgO–C refractory could exceed 4.0 mm under these conditions and its dissolution supplied some MgO to slag. [ABSTRACT FROM AUTHOR]

The photocatalytic evolution of hydrogen is a potential method for acquiring green hydrogen from nature. Unfortunately, this technique has limitations owing to a lack of knowledge of the reaction processes, despite the fact that in recent decades significant scientific adva'nces have been achieved regarding catalyst design and efficiency. Often neglected in favor of heterojunction engineering or band engineering, the chemical environment of catalysts has long been the subject of research. This article offers insight into the photocatalytic H 2 evolution from the surface reaction. It was underlined that reactant adsorption and surface charge extraction have a significant impact on the enhancement of photocatalytic H 2 evolution and anti-photocorrosion properties of the catalyst, which are also strongly connected to the catalyst's chemical environment. Specifically, this study emphasizes the significance of surface/interface condition, type and concentration of electrolytes, reaction solvents, and temperature, etc., during photocatalytic H 2 development, all of which play a crucial role in surface charge extraction of catalyst. In addition, the surface kinetics, adsorption and diffusion of reactants, the selectivity of intermediates, etc., are emphasized for designing highly efficient reaction systems in future applications of photocatalysis. It was shown that more comprehensive methodologies are urgently required for constructing efficient and stable photocatalytic reaction systems by merging catalyst design and reaction environment manipulation. This review may provide fresh ideas for the use of photocatalytic solar energy conversion. [Display omitted] • Photocatalytic thermodynamics and surface reaction kinetics were briefly summarized. • It was addressed the influence of reaction circumstances on H 2 evolution and apparent kinetics. • Emphasized the importance of an external factor in the research of photocatalytic apparent kinetics. • Discussed the prospect of inhibiting photocorrosion by increasing surface response. [ABSTRACT FROM AUTHOR]

• The sorption behaviour of ROX on ferrihydrite has been systematically investigated. • H-bonding and surface complexation reactions are the main mechanisms that control the sorption of ROX. • The 2D-COS analysis revealed that substituents were involved in the dynamic binding process. • The H-bonding reaction takes precedence over surface complexation and is more susceptible to external interference. • More substituents were altering the sorption process of phenylarsonic compounds. The retention and fate of Roxarsone (ROX) onto typical reactive soil minerals were crucial for evaluating its potential environmental risk. However, the behavior and molecular-level reaction mechanism of ROX and its substituents with iron (hydr)oxides remains unclear. Herein, the binding behavior of ROX on ferrihydrite (Fh) was investigated through batch experiments and in-situ ATR-FTIR techniques. Our results demonstrated that Fh is an effective geo-sorbent for the retention of ROX. The pseudo-second-order kinetic and the Langmuir model successfully described the sorption process. The driving force for the binding of ROX on Fh was ascribed to the chemical adsorption, and the rate-limiting step is simultaneously dominated by intraparticle and film diffusion. Isotherms results revealed that the sorption of ROX onto Fh appeared in uniformly distributed monolayer adsorption sites. The two-dimensional correlation spectroscopy and XPS results implied that the nitro, hydroxyl, and arsenate moiety of ROX molecules have participated in binding ROX onto Fh, signifying that the predominated mechanisms were attributed to the hydrogen bonding and surface complexation. Our results can help to better understand the ROX-mineral interactions at the molecular level and lay the foundation for exploring the degradation, transformation, and remediation technologies of ROX and structural analog pollutants in the environment. [Display omitted] [ABSTRACT FROM AUTHOR]

To create hybrid composites for highly effective photocatalytic hydrogen evolution reactions, the photogenerated charge separation efficiency at the hybrid interface and the surface reaction kinetics at the reactive sites are key factors. In this work, CoFe hydroxide nanosheets prepared by dealloying were first mixed with graphitic carbon nitride (g-C 3 N 4) to synthesize a CoFe 2 O 4 /g-C 3 N 4 composite with strong Co-N bonds at the interface by a simple hydrothermal method. It was found that the presence of Co-N bonds between the components in the composites enhances the separation and transfer by photogenerated carriers at the composite interface. Furthermore, the presence of Co-N bonds enhanced the synergistic effect of the hybrid, which significantly boosts their photocatalytic performance in comparison to their counterparts. Under full-spectrum light, the composite photocatalyst has a greater efficiency of photocatalytic water H 2 evolution (6.793 mmol/g−1·h−1) and exceptional stability when compared to pure g-C 3 N 4 (0.236 mmol/g−1·h−1) and CoFe 2 O 4 (0.088 mmol/g−1·h−1). Under visible irradiation, the photocatalytic activity of the composite (0.556 mmol/g−1·h−1) for H 2 evolution increased by factors of 28.37 and 75.8 when compared to pure g-C 3 N 4 and CoFe 2 O 4 , respectively. [Display omitted] • The CoFe 2 O 4 /g-C 3 N 4 composite with strong Co-N bonds. • The transfer photogenerated carriers are improved by the Co-N bonds. • The presence of Co-N bonds enhanced the synergistic effect of the hybrid. [ABSTRACT FROM AUTHOR]

With multi-stimuli responsive luminescence, the ZnS-based optical materials show bright potentials in applications for advanced anti-counterfeiting, which still confront with poor ultraviolet (UV) resistance and photobleaching. This work proposes an efficient surface modification strategy to construct a core-shell ZnS:KBr,Mn2+@CaZnOS (ZKM@CaZnOS) composite phosphor, where a uniform thin layer of Ca(OH) 2 firstly deposits on the ZKM particles then the controllable combination reaction on the surface generates an intimate layer of CaZnOS. The core phosphor ZKM possesses excitation wavelength dependent dynamic luminescence by combining the intrinsic luminescence and Mn2+ emission. The inert shell acts as a protection layer to greatly enhance the UV-resistance of the ZKM phosphor. After exposure to UV irradiation for 45 days, the ZKM@CaZnOS maintains over 90% of the initial luminescent intensity while the starting ZKM remains about 50%. The modified ZKM@CaZnOS phosphors show promising application in the portable UV resolvable anti-counterfeiting. [Display omitted] [ABSTRACT FROM AUTHOR]

A novel Pd/PdO and hydrous RuO 2 difunction-modified SiO 2 @TaON@Ta 3 N 5 core-shell structured nano-photocatalyst was synthesized successfully, which displayed excellent photocatalytic activity for overall water splitting into H 2 (473.52 μmol−1·g−1·h−1), about 2.86 times higher than unmodified SiO 2 @TaON@Ta 3 N 5 (165.74 μmol−1·g−1·h−1), under the visible-light irradiation with the wavelength ≥420 nm, without any sacrificial agent, as well as excellent stability against photocorrosion. The apparent quantum yield (AQY) reaches to 0.253% under irradiation intensity of 12 mW cm−2 at 420 nm. The spatially separated Pd, PdO and RuO 2 clusters were decorated on the Ta 3 N 5 surface to construct local multi-heterojunctions, which were confirmed to enhance the light absorption capability, drive efficient separation of charge carriers and directional transfer, and promote surface redox reaction kinetics of HER and OER. The trace modification of metallic Pd clusters and TaN could mainly contribute to the significant decrease in the HER overpotential, while PdO exhibited a stronger contribution than RuO 2 for OER catalytic activity. The synergetic mechanism of enhanced photocatalytic overall water splitting for hydrogen production was discussed in detail. Thus the combination of core-shell heterojunction construction and surface difunction modification provides a promising strategy for develop efficient all-in-one photocatalysts for solar overall water splitting. The spatially separated Pd, PdO and RuO 2 clusters were decorated on the Ta 3 N 5 surface to construct local multi-heterojunctions, which enhanced the light absorption capability, drove efficient separation of charge carriers and directional transfer, and promoted surface redox reaction kinetics of HER and OER. [Display omitted] • Novel Pd/PdO and hydrous RuO 2 difunction-modified SiO 2 @TaON@Ta 3 N 5 nanophotocatalyst. • AQY for overall water-splitting into H 2 reached to 0.253% at 420 nm. • Spatially separated Pd, PdO and RuO 2 clusters were decorated on the Ta 3 N 5 surface. • Local multi-heterojunctions drove efficient separation of charge carriers. • Synergetic effect resulted from Pd/PdO and hydrous RuO 2 decorating. [ABSTRACT FROM AUTHOR]

In surface-enhanced Raman scattering (SERS) applications, the MAX phase is typically acid etched to address deficiencies, while the more accessible alkali corrosion products are neglected. The woolen ball-like K 2 Ti 8 O 17 (KTO) nanomaterial is synthesized via an efficient hydrothermal surface corrosion reaction between KOH solution and MAX phase Ti 2 AlN, which exhibits excellent SERS capabilities to the contaminating dyes. The enhancement factors are 2.33 × 105, 1.04 × 105 and 2.22 × 105 with lowest limits of detection of 10−7 M, 10−6 M and 10−7 M for crystal violet, rhodamine 6G and methylene blue, respectively, indicating that KTO is a highly desired candidate of SERS substrate material. Meanwhile, KTO shows excellent SERS performance for chrysoidine in simulated seawater, which proves its practical application value. The excellent SERS performance of KTO is attributed to the charge transfer mechanism, which is made possible by the appropriate energy band structure and the robust adsorption capacity. In conclusion, a novel method for the synthesis of KTO is investigated and its reaction process and enhancement mechanism are exhaustively characterized and described. The woolen ball-like KTO exhibits remarkable SERS properties and potential applications. [ABSTRACT FROM AUTHOR]

The co-combustion of various ultra-low volatile coal-based solid fuels (UVCFs) under oxy-fuel condition could consume semi-coke and residual carbon cleanly and efficiently. However, the fuel-nitrogen (fuel-N) migration behaviors of various UVCFs blends in O 2 /CO 2 atmosphere are still unclear. In addition, the heterogeneous reactions on surfaces of char could also affect the synergistic effects between various UVCFs blend. Here, the fuel-N migration features of various UVCFs in O 2 /CO 2 atmosphere were investigated by Chemkin simulation and the oxy-fuel co-combustion mechanism of various coal-based solid fuels (OCF mechanism) included heterogeneous reactions was developed. Moreover, the methods of sensitivity and rate of production analyses were both employed to clarify the synergistic effects on nitrogen conversion pathways of various blends. The heterogeneous reaction between char and NO (R15) is the key reaction for NO reduction in primary zone. The free radicals OH and H provided by UVCFs could react with main NO precursors NCO, HNCO, HOCN, NH and NH 2 to generate NO. The conversion pathways of HCN to NO are more complex than those of NH 3 to NO. The rises of residual carbons proportions and temperature in primary zone (T 1) could both reduce the NO formation amount due to the promoted R15. The sensitivity coefficients (S) on NO formation of 50% SS/50% CR blend in the burnout zone are lower than those of 50% SS/50% FR blend. The transformations of HNCO, HNO and NO 2 to NO and the heterogeneous reactions of NO could both be enhanced with the O 2 concentration in burnout zone. The increasing burnout air position (P b) results in the rise of NO generation owing to that the NO reducing reactions R15 and R16 are greatly inhibited with the P b raised. The present study could be beneficial for the clean and effective utilization of UVCFs, together with the reduce of NO x emission and realization of carbon neutral in China. [Display omitted] [ABSTRACT FROM AUTHOR]

An interlayer structure hybrid wrinkled silica titania (WST) loaded on graphitic carbon nitride (g-C 3 N 4) was successfully constructed using facile microwave-assisted solid-state technique. The as-prepared materials were characterized using N 2 adsorption-desorption, XRD, FESEM, UV–Vis DRS, FTIR, and TEM analysis. The photocatalytic degradation of 2-chlorophenol (2-CP) towards visible light illumination (150 mW/cm2) is following the sequence: 10 wt% WST@CN (91%) > 5 wt% WST@CN (65%) > g-C 3 N 4 (63%) > 15 wt% WST@CN (58%) ˃ WST (50%). The supreme photocatalytic performance of 10 wt% WST@CN was owing to the WST morphology that more concealed between stacked layer of g-C 3 N 4 , as a consequence of the stronger interaction between "nitrogen pots" of the g-C 3 N 4 and Si/Ti species of the 10 wt% WST, and thus, enhanced the efficiency of charge separation. These criteria provide better charge carrier mobility for enhanced visible light driven photocatalytic performance. The kinetic studies revealed that the photocatalytic degradation of 2-CP using 10 wt% WST@CN obeyed a model of pseudo-first order, with the surface reaction being the rate determining step. Subsequently, the scavenger study confirmed that hydroxyl radicals that absorbed on the catalyst surface play a major role over 10 wt% WST@CN as emerged from the mechanism of Z-scheme. It is notable that the interfacial of WST@CN composite could appear as an excellent catalyst for its useful application for endocrine disruptive wastewater treatment. [Display omitted] • WST@CN composites were synthesized via microwave-assisted solid-state method. • 10 WST@CN shows the highest photodegradation of 2-CP (91%). • The dendrimer morphology of WST was concealed on the stacked layer of g-C 3 N 4. • 10 WST@CN possesses the strong interaction between nitrogen pots and Si/Ti. • Z-scheme has preserved the strong redox potential for enhancement of performance. [ABSTRACT FROM AUTHOR]

Herein, noble-metal free Ni–Te/Ni–P dual co-catalysts are investigated as attractive candidates for improving the photoelectrochemical (PEC) performance of CdTe photocathodes. The Ni–Te/Ni–P dual co-catalysts are deposited on CdTe photocathodes via pulse-reverse electrodeposition and post annealing. The Ni–Te/Ni–P catalyzed CdTe photocathodes show a remarkable PEC performance, especially in terms of the photocurrent density, which is approximately 11.06 times higher than that of the pristine CdTe photocathode. The Ni–Te/Ni–P dual co-catalysts boost the catalytic activity via enhanced charge transfer and surface reaction kinetics. The photogenerated electrons and holes are effectively separated by the Schottky contact between the Ni–Te/Ni–P dual co-catalysts and the CdTe absorbing layer. Thus, the rational design of the CdTe photocathode with the Ni–Te/Ni–P dual co-catalysts can dramatically enhance the PEC performance of the CdTe photocathodes. [ABSTRACT FROM AUTHOR]

The conversion of CO 2 to valuable chemicals by photocatalysis has attracted widespread interesting. Owing to the linear structure of CO 2 molecule with strong C O bond, the surface reaction is considered as one of the main issues to restrict the conversion efficiency. Herein, soluble UiO-66 has been developed as co-catalyst to enhance the photocatalytic performance for CO 2 reduction. The soluble UiO-66 has presented the performance ca. 1.5 higher than the insoluble version, yielding 30.6 µmol/h for CO 2 to CO conversion by using 5.0 mg sample. This improvement can be attributed to the preserved framework by soluble UiO-66. Therefore, the chemisorption of CO 2 molecules can be improved, boosting the reduction reaction for CO production. This research provides a new path for a rational design of metal-organic framework (MOF) for photoredox catalysis, meanwhile inspiring advanced application of MOF catalysis with the soluble manner. The difference between the general UiO-66 and soluble UiO-66 in CO 2 photocatalytic reduction reaction. [Display omitted] • A soluble UiO-66 MOF material is synthesized for CO 2 photoredox catalysis. • The product yield over soluble UiO-66 is much higher than the insoluble UiO-66. • The soluble UiO-66 maximizes the active sites, similar to a homogeneous catalyst. • This research has provided a path for design of MOFs by usage of its solubility. [ABSTRACT FROM AUTHOR]

A closed kinetic model of the interaction of dissociated air with the surface of heat-shielding material SiO 2 (β-cristobalite) has been developed. To describe heterogeneous processes, a cluster approach was used, in which the surface of a material with a crystal structure was modeled by a cluster that conveys the stoichiometry of the crystal and the valence states of the atoms lying on the surface. The potential energy surface was calculated using the electron density functional theory (DFT) method with an extended hybrid functional combined with Lee–Yang–Parr correlation functional (X3LYP). The correlation-consistent polarized triple-zeta valence basis set cc-pVTZ was used as the basis functions. The rate constants of the elementary stages (adsorption/desorption, associative and impact recombination) are obtained according to the transition state theory adapted to surface reactions. The calculated rate constants of the processes under consideration were approximated in the generalized Arrhenius form in the temperature range 500–2200 K and compared with the phenomenological models available in the literature and numerical calculations by other authors. • A closed kinetic model of the interaction of dissociated air with the surface of SiO 2 material has been developed. • The potential energy surface of gas -surface interaction was calculated by the DFT method (X3LYP/cc-pVTZ). • The rate constants of adsorption-desorption, impact and associative recombination processes were calculated. [ABSTRACT FROM AUTHOR]

Alginate hydrogel beads were loaded with bimetallic NiPt nanoparticles by in situ reduction of the respective polymer matrix containing precursor metallic ions using a NaBH 4 aqueous solution. The alginate hydrogel beads loaded with NiPt nanoparticles were characterized by TEM, AAS, FT-IR, TGA, XPS, and oscillatory rheometry. The prepared hybrid hydrogels were proven to be effective as catalytic materials for the hydrolysis of ammonia borane (AB) for quantitative hydrogen generation using catalytic loadings of 0.1 mol%. In addition, the reaction mechanism of the hydrolytic reaction using NiPt loaded alginate hydrogel beads was determined by Langmuir-Hinshelwood model. The experimental results showed that the reaction mechanism consisted of an initial fast adsorption of reactants at the surface of the nanoparticles, followed by a rate-limiting surface reaction. The NiPt nanoalloys exhibited an enhanced behavior for hydrogen generation with a maximum TOF of 84.1 min−1, almost 71 % higher compared to monometallic platinum atoms, and likely related to a synergistic interaction between both metals. Finally, the hydrogel matrix enabled the material to be easily recovered from the reaction medium and reused in further catalytic cycles without desorption of active nanoparticles from the material. [Display omitted] [ABSTRACT FROM AUTHOR]

The application of magnesium oxide (MgO) nanoparticles as a candidate material for antibacterial purposes has been limited by their relatively low antibacterial activity. In this study, antibacterial MgO nanoparticles were synthesised in one step using magnesium nitrate and citric acid as raw materials using an economical and environmentally friendly microwave-assisted solution combustion approach, while the effect of the pH of the reaction system (2, 4, and 7) on the structure and antimicrobial properties of the synthesised MgO nanoparticles was investigated. X-ray diffraction (XRD) analysis demonstrated the formation of cubic-phase MgO nanoparticles, and electron microscopy studies confirmed that MgO nanoparticles synthesised at a precursor solution pH of 4 had uniform size distribution with a small microcrystalline size (∼19 nm) and spherical granular morphology. In addition, the results of the plate colony counting method showed that the antibacterial rate of MgO-4 against Gram-negative Escherichia coli (106 CFU/mL) at a sample concentration of 100 μg/mL was as high as 99.86 %, which showed excellent antibacterial performance. These findings provide valuable insights into how to increase the degree of oxygen adsorption on the sample surface to participate in the reaction, as well as a potential method for constructing nanomaterials with high antimicrobial activity. • Effect of solution pH value on the process of microwave-induced solution combustion. • Effect of solution pH value on the microstructure and antibacterial activity of MgO nanoparticle. • Controllable synthesis of MgO nanoparticles with high antibacterial activity and its antimicrobial mechanism study. [ABSTRACT FROM AUTHOR]

[Display omitted] • Reaction mechanism of CH 4 by Fe 2 O 3 was revealed via experimental and theoretical methods. • A microkinetic model combining oxygen supply and catalysis was developed for Fe 2 O 3. • Methoxy(CH 3 O) is the key intermediate for CH 4 complete oxidation. • CH 3 O* → CH 2 OO* + H* dominates the overall CH 4 combustion reaction by Fe 2 O 3. Fe-based oxygen carriers are regarded as a promising class of oxygen carriers in the field of chemical looping combustion. However, the elucidation of the detailed microscopic reaction mechanism of oxygen carriers remains a significant challenge. In this work, we combine in situ spectroscopy, density-functional theory (DFT) calculations, and micro-kinetic modelling to reveal the microscopic reaction mechanism of CH 4 combustion on α-Fe 2 O 3. The macroscopic reaction characterization of hematite with CH 4 was carried out on a fixed bed, and gas chromatography (GC) was utilized to detect the combustion products (CO 2 , H 2 O and H 2). Subsequently, in situ spectroscopy and DFT were combined to reveal the detailed pathways for the CH₄ oxidation process. The results indicated that the reaction intermediates evolve from methoxy (CH 3 O*) to the bridged bidentate formate (b-HCOO*) to the monodentate formate (m-HCOO*), which ultimately leads to the formation of CO 2 through a combination of H transfer and lattice oxygen oxidation. A micro-kinetic model was developed which incorporates surface reaction with the oxygen transport. This revealed that CH 3 O* and CH 3 O* → CH 2 OO* are the key intermediates and radical reactions, respectively, for CO 2 production. The elucidation of the reaction mechanism may prove beneficial for the future development of novel Fe-based oxygen carriers. [ABSTRACT FROM AUTHOR]

Combining global optimization of surface species at different chemical environments with electronic structure analysis and IR spectrum calculation including frequency and intensity, the stable arrangement of reactants and its transformation, as well as oxidation pathway were revealed at the molecular level. [Display omitted] • Global optimization and IR spectrum calculation were used to identify surface species. • Effect of reactant's chemical environment on NO adsorption and oxidation was studied. • Arrangement and transformation of NO and NO 2 at different environments were revealed. • Oxidation pathway was elucidated by global optimization, TS and IR calculation. Reactant's chemical environments derived from the type and concentration of surface species on heterogeneous catalysts do great effects on the structures of reactants and reaction pathway. Unraveling the arrangement of surface species and reaction mechanism at different reactant's chemical environments in theory remains a substantial challenge due to the difficulty in obtaining the global stable configuration of surface species on catalysts and the lack of other theoretical evidences for the identification of surface species and reaction pathway. To solve this problem, a protocol combining the global optimization of surface species at different chemical environments with electronic structure analysis and IR spectrum calculation including frequency and intensity was proposed to unravel the arrangement of surface species and their reaction pathway in this work. Using NO adsorption and oxidation on Pt(1 1 1) and O-covered Pt(1 1 1) as a case, their stable structures were obtained by the global optimization; then the origins of the structural transformation of NO and NO 2 at different environments were elucidated by electronic structure analysis; then the structures and reaction pathway were confirmed by comparing the experimental and calculated IR spectra of NO and NO 2 with frequency and intensity. Utilizing this protocol, the stable structures of NO and its transformation, as well as oxidation pathway were revealed under varying chemical environments at the molecular level. It provides solid supports for identifying the stable arrangement of surface species, their transformation and reaction pathway, and can be easily extended to heterogeneous catalysis. [ABSTRACT FROM AUTHOR]

The lowered reaction energy barrier and accelerated dynamic behavior for photocatalytic H 2 O overall splitting (HOS) involving oriented chemisorption, activation and conversion of *H and oxyhydrogen intermediates are crucial for solar energy conversion into H 2 (STH). Herein, the localized heterojunction (Cd-S-Ni) composed of NiS and CdS via. tuning surface atomic arrangement with S atoms as the shared ligands has been constructed to synchronously elevate and optimize Ni 3 d (Ni ε 3d) and S 2 p (S ε 2p) band centers as efficient active sites for chemisorption of oxyhydrogen and *H intermediates with a declined Cd 4 d band center (Cd ε 4d) to suppress reverse reaction. A sustainable STH of 3.21 % under AM 1.5 G has been completed over Cd-S-Ni with a decreased activation energy for H 2 evolution, verified by fs-TAS, in situ DRIFTS and dynamic DFT. These results devote to solving the reaction energy barrier and dynamical bottleneck for HOS by optimizing ε d and ε p. [Display omitted] • Surface atomic arrangement by sharing ligands for solar energy conversion to H 2. • Accurate the construction of d , p -band centers as active redox sites. • In situ studies for carrier transfer dynamics and its surface reaction kinetics. • A stable solar-to-H 2 efficiency of 3.21 % under AM 1.5 G has been achieved. [ABSTRACT FROM AUTHOR]

Aqueous zinc-iodide batteries (AZIBs) are considered to be the promising candidate after lithium-ion batteries due to their low cost and high safety. However, the poor electrical conductivity of iodine and the notorious shuttle effect brought about by resolvable polyiodides have seriously hindered the widespread application prospects of AZIBs. In this work, we develop a sample and effective strategy for synthesizing N-doped hierarchical porous graphitized carbon (CN-Mg-CaCO 3) that shows great potential as a host material for iodine confinement. The unique porous structure with graphitic domains and synergistic effects of surface adsorption and efficient conversion contribute to the high performance of AZIBs, with notable specific capacity (185 mA h g−1 at 0.1 mA g−1), impressive rate capability (114 mA h g−1 at 10 A g−1), and excellent long-term cycling stability (85 % retention after 104 cycles at 5 A g−1). The elaborately constructed conductive carbon skeleton enhances iodine utilization, while the redox reaction of I 2 /I- occurs without the formation of intermediates I 3 -. Additionally, the presence of surface adsorbed Zn2+ leads to enhanced pseudo-capacitance. This research introduces innovative approaches and broadens new ideas for developing cathode materials for AZIBs. [Display omitted] • One-step synthesis of N-doped hierarchical porous graphitic carbons by metallothermic reaction. • The synergistic effect between iodine redox reaction and surface adsorption. • High rate performance and long-term cycling stability are shown. [ABSTRACT FROM AUTHOR]

Achieving efficient artificial nitrogen fixation similar to nitrogenase under mild conditions has always been a goal pursued by human beings, but it remains a huge challenge. Herein, a novel photothermal catalyst UiO-66(Zr-Fe)/Fe-dispersed MXene having nitrogenase-mimicking electron transfer structure and electron donation mechanism is fabricated and applied in a designed gas-vapor-solid bi-phase system for efficient N 2 -to-NH 3 conversion. The complementary role playing of UiO-66(Zr-Fe), Ti 3 C 2 MXene and well-dispersed Fe sites are capable of simulating nitrogenase triple tandem system that in charge of electron generation, electron transfer and N 2 fixation, respectively. In this well-designed catalyst, a remarkably high NH 3 formation rate of 133.2 μmol g−1 h−1 under solar level illumination is recorded. This superior performance of the biomimetic structure is related to the enhanced light-to-matter interaction for effective multi-electron extraction and promoted photothermal response for accelerating surface reaction dynamics. [Display omitted] • Nitrogenase-mimicking photothermal catalyst U6(Zr-Fe)/Fe-MXene is designed. • Gas-Vapor-Solid reaction system is created for photocatalytic nitrogen reduction. • High NH 3 production rate is recorded under solar level intensity. [ABSTRACT FROM AUTHOR]

Soil can release HONO, affecting atmospheric oxidation and tropospheric chemistry processes through the production of hydroxyl radicals (OH) and nitric oxide (NO) via photolysis. However, there is limited field observation of HONO flux, hindering a comprehensive understanding of its emission mechanisms. In this study, a dual open-top chambers system combined with a long path absorption photometer (LOPAP) was employed to measure HONO flux from paddy fields in the Pearl River Delta area (PRD), showing good reproducibility and effectivity to mitigate greenhouse effects. The average HONO flux was 0.77 ± 0.72 ng N m−2 s−1, displaying a diurnal pattern of higher fluxes during the day and lower fluxes at night, similar to previous flux observations. A strong linear correlation between the HONO flux with the product of NO 2 and solar radiation (R2 = 0.90) suggests that surface reactions involving NO 2 and sunlight may dominate HONO production from the paddy fields, surpassing microbial activity within the soil. Given the diversity of field environments, more field observations are needed for assessing emission rates of HONO and understanding underlying mechanisms. [Display omitted] • A system based on dynamic chamber and long path absorption photometer method to measure soil HONO emission was developed. • The parallelism between different chambers was tested under laboratory and field measurement conditions. • The average HONO flux was 0.77 ± 0.72 ng N m−2 s−1, displaying a diurnal pattern of higher fluxes during the day and lower fluxes at night. • Surface reactions involving NO 2 and sunlight may dominate HONO production from the paddy fields. [ABSTRACT FROM AUTHOR]

Zinc metal batteries are expected to be the next generation of energy storage devices due to their high safety, but their application is hampered by irreversible hydrogen evolution reaction and surface side reactions of zinc anodes. Here, a zwitterionic hydrogel electrolyte is reported based on polymerization of acrylamide and 1-(3-Sulfopropyl)-2-Vinylpyridinium betaine, and it exhibits the following advantages: the sulfonic acid group of 1-(3-Sulfopropyl)-2-Vinylpyridinium betaine can be preferentially adsorbed on metal Zinc to avoid side reactions and refine the affinity at the zinc-electrolyte interface; and the coordination of the negatively charged sulfonic acid group with Zn2+ alters the solvation structure of Zn2+, which further improves the restriction ability of side reactions. Consequently, Zn||Zn symmetric batteries can be stabilized for 1, 200 h of plating stripping at 1 mA cm−2. Zn||Cu batteries exhibit an impressive average coulombic efficiency of 99.8 % over a remarkable span of 1, 800 cycles at a current density of 15 mA cm−2. Furthermore, the Zn||MnO 2 /Carbon nanotube batteries have been cycled more than 2, 000 cycles at a current density of 0.5 A g−1, and the zinc hybrid capacitors for more than 18, 000 cycles at 1 A g−1. And an ionic skin (i-skin) based on acrylamide and 1-(3-Sulfopropyl)-2-Vinylpyridinium betaine of polymer hydrogel electrolyte is assembled and it can stably detect physiological signals. A zwitterionic hydrogel electrolyte is constructed based on polyacrylamide/poly(1-(3-sulfopropyl)-2-vinylpyridinium betaine, excellent mechanical strength and high ion conductivity is advocated for zinc metal batteries. The sulfonate anionic groups of the polyacrylamide/poly(1-(3-sulfopropyl)-2-vinylpyridinium betaine side chain with negatively charged can absorb onto Zn anodes to refine Zn-electrolyte interface affinity and prevent the H 2 O molecules in the Zn2+ solvation structure from contacting with Zn anodes. In addition, the sulfonate anionic groups can also guide the Zn2+ migration, and decrease the desolvation energy for fast Zn/Zn2+ reversibility. Moreover, the mechanical property of the hydrogel is enhanced by the Hofmeister effect between –SO 4 2- and polyacrylamide/poly(1-(3-sulfopropyl)-2-vinylpyridinium betaine, to accommodate the deformation of the electrodes. [Display omitted] • The zwitterion hydrogel with high interfacial affinity is fabricated. • The zwitterion hydrogel improves the stability of Zn anodes. • The Zn mental battery/capacitor exhibits outstanding cycle stability and life. • The ionic skin demonstrates stable signal monitoring for various body parts. [ABSTRACT FROM AUTHOR]