In this study, based on the semiconductor catalyst CeO2, a systematic research framework of ‘carrier modification-component regulation-performance optimization’ is proposed, the introduction of non-metal N and Pd effectively modulates the energy band structure of CeO2, reducing the bandgap from 2.54 eV to 2.33 eV and 2.08 eV, respectively. The incorporation of Co regulates the surface electron density of Pd, which significantly enhances charge separation and migration efficiency. The initial turnover frequency (TOF) of the CoPd@N-CeO2 catalyst reaches 4356 h⁻1 under non-light driven conditions and 7080 h⁻1 under light driven conditions, with an activation energy of 51.3 kJ/mol. The addition of H2O and HCOONa is beneficial for the formic acid decomposition reaction toward hydrogen production, the optimal performance is achieved at a formic acid concentration of 1.0 mol/L and the HCOOH to HCOONa molar ratio of 1:1.5. Moreover, the addition of excess bases(NaOH) completely terminates the hydrogen production reaction, while subsequent addition of acid(H2SO4) successfully restarts it, which provides a method for the controllable start-up and shutdown of the formic acid decomposition. This study provides an important theoretical basis and practical reference for the light-driven directional decomposition of formic acid for CO-free hydrogen production.

Particle segregation phenomenon significantly affects the interaction of two feedstocks during coal and biomass co-gasification. The physical separation of the blended char of anthracite and corn stalk prepared under rapid pyrolysis conditions was performed based on the difference in raw material particle size. The physicochemical structures of chars were characterized by X–ray diffraction (XRD), Raman spectroscopy, and BET surface area analysis, while the gasification reactivity was determined using a thermogravimetric analyzer (TGA). Then, the internal relationship between structural parameters and gasification reactivity was explored by progressive grouping correlation method. Also, two calculation methods were used to quantify the synergistic effect. The reaction mechanism was further proposed and the gasification reaction kinetics was studied. The results demonstrated that graphitization degree followed a decreasing trend in the order of separated coal char, blended char, and separated stalk char. ID3/IG was regarded as a reliable indicator for predicting the reactivity of char gasification. The synergistic effect exhibited a dynamic transition from inhibition to promotion. The initial inhibition was attributed to pore blockage and active‑site occupation by polycyclic aromatic hydrocarbons (PAHs) generated from the polymerization of oxygen‑containing compounds. The consumption of carbon matrix and the catalytic gasification of both PAHs and char by active K convert the synergistic effect from inhibition to promotion. Kinetic analysis identified the Modified Volume Model as optimal for char gasification, with apparent activation energy decreasing markedly at higher blending ratios. This work provides insights into particle segregation and synergy in coal and biomass co‑gasification, which can guide process optimization.

In this study, a new pressure stabilization (PS) system composed of a gas stable vessel (SV), PID control system and a reaction vessel (RV), etc. was used to study the dynamic characteristics of methane separation from low concentration coalbed methane com-pared with PV system. A porous medium system was constructed by sodium lignosul-fonate (SL) or calcium lignosulfonate (CL) solution which could will reduce gas-liquid interfacial tension, and enhance methane dissolution and mass transfer. At the same time, a thermodynamic accelerator of cyclopentane (CP), which effectively reduced hydration reaction conditions and improved methane storage rate, was added to the hydration reaction solution. The experiments were carried at 275.15 K and 3.0 MPa, the mass concentration of lignin was 500 ppm, the volume ratio of CP to deionized water was 1:10. The results shown that higher CH4 recovery (66.7%) and higher gas uptake (0.1139 mol) were obtained in PS + SL + CP system, but shorter t90 (154 min) and higher CH4 concentration (69.5%) in the hydrate phase were appeared under PV + SL + CP system, however shorter induction time (9 min) was found in PS + CL + CP system.

With the advantage of achieving simultaneous removal of dust and NOx, fibrous ceramic-based catalytic filter elements (CFEs) have emerged as important multifunctional materials in the field of high-temperature flue gas purification. However, the poor dispersion of the loaded catalyst remains the key bottleneck restricting the denitration performance of CFEs. In this work, acetylacetone, with its strong chelating capability, was employed as a complexing agent during the sol synthesis to regulate the hydrolysis and condensation of the titanium precursor and thus improve the catalyst’s dispersion. The action mechanism of acetylacetone and the structure-activity relationship of the catalysts prepared with different addition amounts of acetylacetone were systematically investigated. The results indicated that the addition amount of acetylacetone significantly affected the catalyst’s physicochemical properties and catalytic activity. At an optimal acetylacetone-to-butyl titanate molar ratio of 2, the titanium sol achieved a minimum average particle size of 149 nm. The corresponding catalyst exhibited good dispersion, large specific surface area, abundant V4+ species, and strong redox ability and surface acidity. Deviation from this optimal ratio (either a lower or higher dosage) increased the sol particle size, which exerted a negative impact on the catalyst’s microstructure. The CFE prepared with this optimal addition amount showed excellent catalytic activity, achieving over 90

With the growing global demand for renewable energy and carbon neutrality, 5-methylfurfural (5-MF), a derivative of furan-based biomass, boasts significant application potential. In this study, combained quantum chemical methods with transition-state theory/RRKM/Master Equation method, the site-specified rate constants of 5-MF with OH were calculated. We found that the rate of hydrogen abstraction reactions surpasses that of hydroxyl addition reactions at T >= 400 K & sdot;In hydroxyl addition reactions, the adducts formed at the C(1) and C(4) sites exhibit negative temperature dependence. The temperature dependence of the bimolecular product (P12 + CHO) at the C(1) site shifts from negative to positive with increasing pressure, while all other bimolecular products show positive temperature dependence. Furthermore, the pressure effect on all bimolecular products is insignificant at high temperatures. The pressure effect for hydroxyl addition reactions is concentrated at 298-600 K. This study provides a key theoretical basis for understanding the oxidation mechanism of furanbased fuels.

Investigating the reaction mechanism between 5-methylfurfural (5-MF) and hydrogen (H) is crucial for understanding the pyrolysis of furan-based fuels. However, current kinetic data on 5-MF + H remains scarce, particularly regarding the influence of methyl side chains, has not been thoroughly studied. In this work, quantum chemical methods and kinetic methods were employed to construct the reaction potential energy surface (PES) and calculate kinetic data for 5-MF + H system. The study indicate that under the high-pressure limit, the total rate of initial H-addition reactions is higher than that of H-abstraction reactions across the entire temperature range. H-abstraction preferentially occurs at the aldehyde site, while the initial H-addition preferentially occurs at C(1) and C(4) site of furan ring. In the temperature range of 298-1300 K and 1atm, the total rate via H-addition dissociation mechanism is higher than that via H-abstraction mechanism. Moreover, the competition between these two reaction mechanisms intensifies progressively, such that when the temperature exceeds 1300 K, the total rate via H-abstraction mechanism surpasses that via H-addition mechanism, becoming the dominant reaction mechanism. The subsequent reaction pathways of these intermediates generated via Haddition dissociation mechanism were explored, along with their temperature and pressure dependences. A comparison with the furfural (FF) + H reaction system indicates that the introduction of methyl branches can significantly enhance the reaction rate. Comparative studies between 5-MF + H and furfural (FF) + H reveal that methyl group significantly enhances reaction rate via H-addition mechanism, and the temperature dependence of two systems is roughly consistent. A detailed kinetic model for 5-MF pyrolysis was constructed based on the calculated results of this work, and the model shows good agreement in predicting fuel consumption. Rate of production (ROP) analysis reveals that, for temperatures above 1300 K, H-abstraction reactions play a more significant role in fuel decomposition than that via H-addition dissociation mechansim, consistent with the calculated reaction kinetics.

In this study, the co-doping of heterogeneous metals(Pd,Ru) and non-metals(B, N) can enhance the light response intensity throughout the entire spectral range(200nm-800nm). In the catalytic system for the formic acid decomposition, the adsorption process of HCOOH is an exothermic process, the adsorption heat increases with the increase of temperature, the adsorption capacity decreases with temperature increases, the rate-determining step of the dehydrogenation and dehydration reactions are C-H bond breakup and O-C bond breakup step, respectively, and the corresponding energy barriers under Pd-based catalysts are 42.48 kcal/mol and 62.13 kcal/mol. The reaction patterns of formic acid on Ru-based catalysts are similar to those on Pd-based catalysts, but the energy barriers for formic acid dehydrogenation and dehydration under Ru-based catalysts are 31.72 kcal/mol and 41.09 kcal/mol. Under the action of the Pd@N-CeO2 catalyst, formic acid decomposes exclusively into CO2 and H2, which is in good agreement with DFT calculations. The introduction of methyl groups onto formic acid molecules reduces the stability of the C-H bonds, consequently lowering the activation energy barrier for the hydrogen evolution reaction to 36.91 kcal/mol. These findings offer a theoretical foundation for the development of formic acid-derived catalysts for hydrogen production.

Abstract The gasification reactivity of coal char is crucial for optimizing gasification processes and reactor design. This study utilized thermogravimetric analysis (TGA) as the primary method to investigate the effect of heating rate on the non-isothermal gasification behavior of Piliqing coal char. High-temperature stage microscopy (HTSM) and thermomechanical analysis (TMA) were used to observe particle morphology and ash shrinkage, complementing the TGA data. TGA results showed that the gasification characteristic temperatures (T i , T m , T f ) of PLQ coal char increased by 57.5, 48.9, and 70.2°C, respectively, with the increase in heating rate. The comprehensive gasification index (S) increased approximately 8.6 times, while the reaction time shortened to 12.0 min. HTSM observations confirmed that the particle area decreased and shrinkage increased with the heating rate, supporting the TGA findings. The high alkalinity index of PLQ coal enables efficient gasification at 950–1000°C, while ash sintering near 1200°C establishes an upper temperature limit to prevent slagging.

With the accelerated deployment of new energy vehicles and the global pursuit of carbon neutrality and carbon peaking goals, lithium iron phosphate (LFP) batteries have become a dominant technology in the energy storage market. The rapid expansion in their production and application has led to a surge in the number of spent LFP batteries, raising urgent concerns regarding resource recovery and environmental sustainability. This review provides a comprehensive overview of recycling technologies for spent LFP batteries, which are categorized into three major routes: (i) conventional metallurgical recycling, including pyrometallurgical and hydrometallurgical processes; (ii) direct regeneration strategies, such as electrochemical and solid-state approaches; and (iii) emerging green technologies, which leverage external fields or novel eco-friendly solvents to enhance recovery efficiency. The fundamental mechanisms, advantages, and limitations of each approach are systematically analyzed and compared. Finally, we also discuss current challenges and future directions for developing high-efficiency, low-cost, and environmentally benign recycling systems. These technological advances are expected to not only promote resource circularity and reduce ecological burdens but also provide a solid foundation for the sustainable evolution of the lithium-ion battery industry.

Applying symmetry boundaries can significantly reduce the computational cost of simulating the coupled heat transfer between a fluidized bed, an immersed horizontal tube, and supercritical CO2 (sCO2). However, the impact of this simplification on the predictive accuracy of sCO2 immersed tube heat transfer performance remains unclear, which is crucial for the development of advanced power generation technologies worldwide. In this work, three-dimensional (3D) and three-dimensional symmetric (3Ds) models were developed based on the Eulerian-Eulerian approach incorporated with the kinetic theory of granular flow. A central composite design was employed to conduct comparative analyses under varying furnace pressures (P), bed temperatures (T), and fluidization numbers (N). Both models yielded heat transfer coefficients (HTCs) close to experimental values, with the 3D model providing slightly higher accuracy. The largest difference between the models appeared in the bed-to-tube HTC (ho), followed by the overall HTC (ko), while the in-tube sCO2 HTC (hi) showed negligible variation. Although ho and ko in both models exhibited similar trends with respect to P, T, and N, their sensitivity to interaction and quadratic terms differed slightly, primarily due to gas and particle convective heat transfer. A quantitative asymmetry analysis further revealed that significant spatial asymmetry in the gas-solid flow by using the 3D model was the main source of these deviations. Importantly, within the tested operating range, the maximum absolute relative error of time-averaged HTCs between the two models remained below 7%, indicating that the 3Ds model can substantially reduce computational cost while maintaining sufficient accuracy for engineering design. This finding provides a practical and internationally relevant pathway to accelerate the design and optimization of sCO2-cooled immersed tubes in large-scale fluidized bed applications, such as next-generation coal and solar thermal power systems.

The nanoparticle agglomerates fluidization exhibits multiscale heterogeneous flow structures, while there is yet no suitable drag models developed to account for the effects of heterogeneous flow structures for nanoparticle agglomerate fluidization. In this study, the effects of drag correction and drag models on the fluidization characteristics of nanoparticle agglomerates in the bubbling and turbulent fluidization are studied using the DDPM approach. The bed expansion behaviors, solid distributions, solid circulation, and the pressure fluctuation are analyzed. Results show that the original Gidaspow drag model over-predicts the bed expansion height in the bubbling fluidization, and the revised Gidaspow drag model or the EMMS drag model resolves reasonable bed expansion height and the stratification of solids concentration. The drag correction yields negligible differences in bed height and flow field between the revised and original Gidaspow drag models in the turbulent fluidization. The revised Gidaspow drag model or the EMMS drag model simulates stronger heterogeneous structures than those of the original Gidaspow drag model. The power spectral density increases then decreases with increasing fluidization velocity and increases with decreasing drag correction coefficient. The sub-signal energy distribution varies similarly. Macro-scale signals exhibit no evident trends, while meso and micro-scale structures are most sensitive to the variation of the fluidization velocity and the drag correction.

This study employed coupled the Computational Fluid Dynamics-Population Balance Model (CFD-PBM) framework and Kinetic Theory of Granular Flow (KTGF) to investigate the flocculation and sedimentation dynamics of polymodal tailings particles in a lab-scale gravity thickener. The Euler-Euler multiphase model and RNG k-epsilon turbulence model are integrated to simulate solid-liquid interactions and turbulent flow characteristics, while flocculation kinetics, including aggregation and breakage mechanisms, are incorporated to quantify particle size evolution. The influence of feed velocity on flow field characteristics and particle flocculation-sedimentation efficiency was analyzed through visualization. The results indicated that the turbulent energy distribution is highly sensitive to the feed velocity. The optimal velocity range (2.0-2.5 m/s) promotes a balanced aggregationbreakage dynamics of particles, stabilizing the formation of larger flocs and enhancing sedimentation. Excessively high feed velocities (>3.0 m/s) induce stronger turbulence, reducing floc size and impairing sedimentation efficiency. Spatial analysis reveals that fine particles (<50 mu m) are widely dispersed, while large flocs (>100 mu m) dominate the underflow solid concentration. The impact of floc size and density on sedimentation was also examined. This study identifies a critical threshold for feed velocity to optimize thickener performance, providing a theoretical basis for process intensification in industrial thickeners.

Efficient hydrogen storage remains a critical challenge for realizing a sustainable hydrogen economy. Solid-state metal hydrides offer a promising solution. This work presents a comprehensive density functional theory (DFT) investigation into the structural, mechanical, electronic, optical, and, crucially, hydrogen storage properties of novel ternary hydrides, XMgNiH4 (X = Sr, Ca). The research results of this work confirm their structural and mechanical stability (negative formation enthalpies, Born stability criteria). Electronic property calculations reveal both compounds are direct band gap semiconductors with potential for multifunctional applications, exhibiting strong optical absorption in the visible spectrum. Most importantly for practical applications, these hydrides exhibit highly favorable hydrogen desorption temperatures of 336.5 K (63.3 °C) for SrMgNiH4 and 326.1 K (53.0 °C) for CaMgNiH4, coupled with gravimetric hydrogen storage capacities of 2.31 wt% and 3.16 wt%, respectively. These findings position XMgNiH4 (X = Sr, Ca) as stable, semiconducting materials with exceptional near-ambient hydrogen desorption characteristics, representing a significant advance in the search for practical solid-state hydrogen storage. This work provides a crucial theoretical foundation for the rational design and future experimental realization of next-generation magnesium-nickel-based materials for sustainable hydrogen energy systems.

Flocculation–thickening is widely used in mineral processing and various chemical engineering fields. The flocculation in the thickener feedwell plays a key role in the tailings slurry thickening process. Hydrodynamic conditions directly affect particle flocculation kinetics and subsequent settling rates, thus determining the overall performance of the thickener. This study employs a multiscale modeling approach to investigate how feed solid concentration affects flow characteristics and flocculation–settling performance in a pilot‐scale deep cone thickener, in which Computational Fluid Dynamics‐Population Balance Model (CFD‐PBM) and a Two‐Fluid Model with Kinetic Theory of Granular Flow (TFM‐KTGF) were applied to simulate flocculation and settling behavior, respectively. Results show that medium solid concentration promotes particle aggregation via optimal turbulence dissipation. Increasing concentration reduces both the initial settling rate ratio of flocs and the settling differential between particle sizes. These findings enhance the understanding of flocculation–thickening mechanisms and support process optimization in solid–liquid separation fields.

In this work, based on the ab initio method, the reaction mechanism of the low-temperature oxidation of 2- furfuryl alcohol (2FFOH) is studied. (2-furyl)(hydroxy)methyl (furylCHOH, labeled as R) and O-2 were taken as the bimolecular reactants, and the energy diagram was determined by a high-level quantum chemical method (CCSD(T)/ CBS//M05-2X/jun-cc-pVTZ). The equilibrium geometry and vibrational frequencies of the reactants, intermediates, transition states, and products were determined by the M05-2X/jun- cc-pVTZ method. Then, the Rice-Ramsperger-Kassel-Marcus/Master equation method was used to calculate the temperature- and pressure-dependent rate coefficients. O-2 addition to furylCHOH needs to overcome energy barriers of 2.35-7.26 kcal/mol to generate three kinds of peroxide radicals, 2-[(2-furyl)(hydroxy)methyl]dioxidanyl (RO2 alpha), 2- {2-[(Z)-hydroxymethylidene]-2,3-dihydro-3-furyl}dioxidanyl (RO2 gamma) and 2- {5-[(Z)-hydroxymethylidene]-2,5- dihydro-2-furyl}dioxidanyl (RO2 epsilon). The calculation results show that peroxide RO2 pound is the main product when the reaction temperature does not exceed 800 K at 1 atm. Moreover, furfural (P21) and HO2 become dominant when temperature is above 800 K at 1 atm, which are formed via concerted HO2 elimination mechanism of three peroxides. The slow reaction rate of RO2 alpha -> INT1 via an intramolecular 1,5 H-shift indicates the trend of low oxidation reactivity of 2FFOH.

Accelerating lithium polysulfide conversion by catalytic effect of host materials in sulfur cathodes is an effective strategy for improving lithium sulfur batteries. In this work, amount of sulfur vacancies is quantitatively regulated to obtain MoS2-x with abundant defects mainly including atom vacancies and edge dislocations. It is found the defects can trigger phase transition from 2H-MoS2 to 1T-MoS2; more interestingly, the defects in 1T-MoS2 provide stronger catalytic ability for polysulfide conversion than those in 2H-MoS2. Furthermore, doping of cobalt in non-stoichiometric MoS2-x can stabilize 1T-MoS2 even with sulfur vacancies as high as 32 %. Acting as catalytically active sites, the abundant and stable defects significantly enhance electrochemical kinetic of the sulfur cathodes. The nitrogen-doped graphene-supported S/Co0.22-MoS1.36 electrode demonstrates an excellent long-cycle stability at 1C, remaining 591.8 mAh g-1 after 1200 cycles with a coulombic efficiency of 98.8 % and a decay rate of 0.032 %. Even under extreme conditions such as a high areal sulfur-loading of 14.3 mg cm-2 and lean electrolyte of 4 mu L mg-1, the S/Co0.22-MoS1.36 electrode achieves an initial areal capacity of 12.37 mAh cm-2 with satisfactory cycling stability. These results provide novel insight and an alternative approach to developing host materials for high-performance lithium sulfur batteries.

The co-combustion of major solid waste such as corn stalk (CS) and polyethylene plastic (PE) can enhance the utilization of hydrocarbon resources and reduce the dependence on fossil fuels. The differences in the properties of feedstock can lead to mixed segregation, which makes the contact state of particles uncertain and unevenly distributed in reactor during co-combustion process. The co-combustion characteristics and synergistic effects of CS and PE under different placement methods were explored using a rapid heating thermogravimetric analysis. The Coats-Redfern method was further employed to evaluate the thermokinetic behavior, and then the reaction mechanism was proposed. Results showed that the comprehensive combustion index of PM (evenly physical mixtures) increased 0.874 x 10-10 min-2 center dot degrees C-3 to 8346.3 x 10-10 min-2 center dot degrees C-3 as the heating rate increased from 10 K/min to 1000 K/min. A similar trend of increasing combustion index also applied to the CT (CS on top of PE) and PT (PE on top of CS) placement methods, indicating that the heating rate could significantly improve the cocombustion reactivity of mixtures on the whole. However, the combustion intensity at the heating rate of 750 K/ min was higher than that at 1000 K/min in the local temperature range of 210-290 degrees C. Notably, the closer contact between PM particles promoted more efficient reactivity at 1000 K/min. The conversion of CT in the lowtemperature region was the highest at high heating rates, followed by PM and PT, while the order of conversion was PM, PT, and CT in the high-temperature region. The negative deviation was much larger than the positive deviation, indicating that the synergistic effect of the whole co-combustion process was variable. Here, a strong and beneficial synergistic effect in the temperature range of 260-530 degrees C was observed. The Coats-Redfern method could well describe the combustion process in different reaction stages, and the activation energy of mixtures increased first and then decreased with the reaction. Meanwhile, the negative value of entropy change indicated that the co-combustion process transitioned from more disordered to ordered states. Thus, the work was beneficial for guiding the operation and segmented reactor design of mixtures with different distribution states under actual working conditions.

Hydrogen fuel is considered to be one of the most potential energy sources that can replace fossil fuels in the future. Liquid organic hydrogen carrier formic acid (FA, HCOOH) has been widely concerned in hydrogen production due to its low price, high hydrogen content and the characteristic of easy storage and transportation. The catalyst design and synthesis play an important role in the hydrogen production from FA. The heterogeneous catalysts have become the main focus of research on hydrogen production due to their advantages of more stable, easier separation and higher recycling. In the review, the development of heterogeneous catalysts (reactive metal, catalyst carrier) in catalyzing formic acid decomposition to produce hydrogen are summarized systematacially, the influence of key factors on the overall catalytic hydrogen-producing activity of FA are described in detail. Meanwhile, the review introduces the application of machine learning in catalytic reactions, especially in the strategy of improving the hydrogen production of FA. In the end, the future development trend of hydrogen production from catalytic FA decomposes is prospected. This review can provide a reasonable theoretical basis for designing novel catalysts with high activity and economy in formic acid decomposition to produce hydrogen, and also brings enlightenment for the research direction of formic acid hydrogen production technology.

Dilution plays a significant role in the flocculation process, which relies on the structure and dimensions of the dilution port. The dilution port was optimized by the hybrid modelling approach between Response Surface Methodology (RSM) and Computational Fluid Dynamics (CFD), considering the interactive impact of sidewall immersion length (L), reference angle (alpha) to bending pipe, and width of the cuboid (W). Batch simulation tests were performed to explore the effect of structure and dimension on dilution quantity. A quadratic regression model forecasted the optimal feedwell would be capable of a self-diluting water volume of 1.53 L/s compared to the basic case of negative1.32 L/s, and the alpha was most sensitive factor that influence the dilution quantity. Subsequently, the flow characteristics and flocculation performance were compared between the two cases using the coupled CFD-Population Balance Model (PBM) approach. Results showed that the outer well was subdivided into four zones following the predicted variation of floc size along the vertical direction. The optimal case exhibited better flocculation performance than the basic case evaluated by the mean floc size distribution in and around the feedwell, thereby guiding the design of feedwell dilution ports for enhancing the flocculation performance.