Abstract:The continuous growth of carbon dioxide(CO2)emissions exacerbates global ecological degradation,leading to a series of environmental issues such as climate change and ocean acidification.Reducing CO2 emissions has therefore become a critical challenge for sustainable development.Light olefins,serving as essential feedstocks and platform molecules in the chemical industry,are widely used to produce various value-added chemicals.Unlike conventional feedstocks and processes for olefin synthesis,the conversion of CO2 into light olefins not only enables resource utilization of CO2 but also reduces dependence on petroleum resources,representing a promising approach that benefits the environment,energy security,and the economy.Currently,two main pathways for CO2 hydrogenation to light olefins are widely reported:the CO2-Fischer-Tropsch to Olefins(CO2-FTO)pathway via CO as an intermediate,and the CO2-Methanol to Olefins(CO2-MTO)pathway via methanol.The CO2-FTO pathway achieves high CO2 conversion,but the C—C coupling is uncontrollable,resulting in a product distribution that follows the Anderson-Schulz-Flory(ASF)model,which limits the selectivity toward light olefins.In contrast,the CO2-MTO pathway breaks the ASF distribution constraint and enables higher light olefin selectivity;however,it suffers from low CO2 conversion and high CO byproduct selectivity.This review systematically summarizes the reaction processes,mechanisms,and catalyst modification strategies employed to enhance catalytic performance for both pathways.For the CO2-FTO route,modification strategies primarily focus on Fe-based catalysts,including the doping of promoters(e.g.,alkali metals,transition metals)and the optimization of supports(e.g.,oxides,carbon materials).For the CO2-MTO route,strategies are discussed from three perspectives:metal oxides,zeolites,and their coupling methods.Additionally,a recently reported alternative pathway(i.e.,RWGS followed by CO hydrogenation)is briefly outlined.Finally,the advantages and limitations of different modification strategies across pathways are summarized,and future research directions are proposed.Overall,CO2 hydrogenation to light olefins represents a sustainable chemical production route with broad prospects for development.

Abstract:As a key energy conversion technology adapting to China's resource endowment of"rich in coal,poor in oil,and scarce in gas",the Fischer-Tropsch synthesis(FTS)technology has achieved a leap from laboratory research to large-scale industrialization.It has demonstrated remarkable effects in safeguarding China's energy security,providing a variety of high-value-added products,and producing clean fuels.However,the coal-based FTS technology has relatively high carbon emissions,which poses a prominent contradiction with China's"dual carbon"goals.The CO2 emission per ton of its products is as high as 6.86-9.00 tons,making emission reduction and transformation an imminent task.Sources of carbon emissions in multiple links of FTS are systematically analyzed,and technical progress and engineering practices of low-carbon FTS in recent years are reviewed from four core paths:Research and development of low-carbon catalysts,process integration and optimization,integration of carbon capture and storage(CCS),and substitution of renewable carbon sources.The role of hydrophobic modified catalysts,pure-phase iron carbide catalysts,and promoter-modified catalysts in inhibiting CO2 generation is focused on expounding.Some of these catalysts have achieved a CO2 selectivity as low as 5％,with the carbon utilization efficiency reaching up to 90％.Process optimization schemes such as cascade utilization of waste heat,integration with the integrated gasification combined cycle(IGCC)power generation system,and coupling with green electricity and green hydrogen are also analyzed.The application status and challenges of CCS technology in multiple links of FTS are sorted out,and the technical paths and prospects of using CO2 and biomass as renewable carbon sources are discussed.Among the related technologies,the production of gasoline via CO2 hydrogenation and the production of green aviation fuel via biomass-based FTS have been realized in kiloton-scale pilot operation.At present,significant progress has been made in low-carbon FTS technology in the fields of catalysts,process optimization,carbon treatment and substitution.However,in engineering practice,there are still problems such as the need to verify the stability of hydrophobic catalysts,the high cost of CCS technology,and the difficulty in achieving stable supply of biomass raw materials,which require continuous research efforts in the future.

Abstract:The Si/Al ratio of Cu-ZSM-5 zeolites is systematically investigated to regulate the catalyst structure and performance in the selective oxidation of methane to methanol under mild conditions.A series of Cu-ZSM-5-X(CZX)catalysts with varying Si/Al ratios are prepared via wet impregnation.Their physicochemical properties are characterized in detail using techniques such as X-Ray Diffraction(XRD),N2 physisorption,X-Ray Photoelectron Spectroscopy(XPS),and Electron Paramagnetic Resonance(EPR).Results reveal that the Si/Al ratio governs the distribution of copper valence states.Among the series,CZ50(measured Si/Al=44.58)possesses the highest proportion of active Cu+sites,with copper being highly dispersed on the zeolite support.Under reaction conditions of 70℃,3 MPa CH4,and 0.5 M H2O2 as the oxidant,CZ50 exhibits optimal catalytic performance,achieving a methanol productivity of 46.46 mmol·gcat-1·h-1 with 86.22％selectivity.This performance significantly surpasses that of catalysts with other Si/Al ratios.Mechanistic studies indicate that Cu+sites efficiently activate H2O2 to generate·OH radicals,which subsequently attack methane to form the key·CH3 intermediate.In situ IR spectroscopy combined with radical-quenching experiments confirms that the distinct electronic structure of CZ50 effectively stabilizes this methyl intermediate,thereby inhibiting deep oxidation to CO2.Through precise tuning of the zeolite Si/Al ratio,the valence state of copper active centers is modulated to favor the formation of highly efficient and stable Cu+sites.This strategy achieves highly productive and selective conversion of methane to methanol under mild conditions.The optimized CZ50 catalyst demonstrates methanol yields that exceed most reported systems,representing a key advance toward the practical realization of direct methane conversion and providing a novel design principle and a solid theoretical foundation for developing efficient,stable non-precious-metal catalysts for methane valorization.

Abstract:Renewable energy sources are receiving increasing attention in order to meet the energy needs of social development and mitigate the effects of greenhouse gases.Advances in hydrogen production technology from renewable energy sources have enabled the sustainable conversion of CO2 into high-value aromatic hydrocarbons via hydrogenation,offering a promising a pathway for CO2 emission and carbon recycling.Aromatics,as essential basic chemicals,are widely used in polymers,fuel additives,pharmaceutical intermediates,and other industries.However,due to its high thermodynamic stability and chemical inertness,the efficient activation and directional conversion of CO2 molecules remain a significant challenge.CO2 hydrogenation to aromatics primarily proceeds via two pathways:methanol intermediate route and modified Fischer-Tropsch synthesis route.Both routes rely on bifunctional catalysts,typically composed of metal oxides(or iron carbides)coupled with zeolites.The methanol-intermediate route first converts CO2 into methanol or its derivatives through hydrogenation,followed by further aromatization on the acidic sites of the zeolite.This route exhibits high aromatics selectivity but suffers from limited CO2 conversion The modified Fischer-Tropsch synthesis route,on the other hand,converts CO2 into CO via the reverse water-gas shift(RWGS)reaction,followed by the Fischer-Tropsch step to produce olefin intermediates,which are finally aromatized on the zeolite to generate aromatic hydrocarbons.This route achieves higher CO2 conversion activity but exhibits a broad product distribution,lower aromatics selectivity,and a tendency for excessive hydrogenation to produce alkanes.How to synergistically improve high CO2 conversion,high aromatic selectivity and long-term catalyst stability remains a pivotal issue in this field.This article focuses on thermal catalytic CO2 hydrogenation to aromatic hydrocarbons,systematically reviewing recent research progress in this area.Based on the two mainstream reaction systems mentioned above,the catalyst design and regulation strategies are first examined.These include the construction of composite oxides,the introduction of promoters in iron carbide-based catalysts,carrier optimization and innovative preparation methods,as well as modulation acidity,pore structure,and morphology of zeolites.These approaches aim to enhance the synergy among active sites and promote the transfer and transformation of reaction intermediates.Subsequently,the tandem catalysis,the hydrocarbon pool mechanism,hydrogen transfer mechanisms are elaborated upon.Strategies for optimizing reaction pathways through the directed enhancement of intermediates and synergistic catalysis to improve target product selectivity are also discussed,with the goal of improving selectivity toward target products.In parallel,catalyst deactivation behaviors are analyzed,including sintering and migration of metal oxides,phase transformation of iron carbides,and coke deposition on zeolites,providing a theoretical foundation for the development of long-term stable catalyst.Finally,opportunities and challenges are outlined,emphasizing that precise catalyst design,multi-scale investigation of reaction mechanisms,process integration and system optimization,and innovative reaction pathways are key research priorities.This review aims to offer forward-looking research directions and strategic references for the future development of this field.

Abstract:Metal hydride hydrogen storage is regarded as having broad application potential in the future hydrogen energy industry due to its safety and high hydrogen storage density.However,the hydrogen absorption and desorption processes are accompanied by intense exothermic/endothermic reactions.During cycling,hydrogen storage alloys are prone to repeated expansion and contraction,resulting in a decrease in thermal conductivity and a decline of hydrogen absorption and desorption performance.Therefore,thermal management technology is recognized as the critical element for enhancing hydrogen absorption and desorption performance.Research progress in metal hydride hydrogen storage reactors over recent years is summarized,with a focus on reactor geometry,modification of hydrogen storage materials,external cooling systems,and internal heat exchange structures including fins,circular tubes and helical tubes.Results show that reactors with different geometries exhibit distinct characteristics in heat transfer efficiency and space utilization.Doping high thermal conductivity media and optimizing the heat exchange structures are found to significantly improve temperature uniformity and to shorten hydrogen absorption and desorption time,while hydrogen storage capacity is reduced.Although external cooling systems can enhance the overall heat transfer capacity of the hydrogen storage reactor,internal cooling structures are regarded as more effective in alleviating local overheating.Complex fin structures and helical tube structures are demonstrated to excel in improving heat exchange efficiency and reducing temperature gradients.Although manufacturing cost and structural complexity remain application barriers,a solid foundation for the scaled application and engineering deployment of metal hydride hydrogen storage reactors is established by continuous innovation in thermal management technologies.

Abstract:Against the backdrop of increasing global energy demand and growing carbon emission pressures,the development of efficient and clean energy conversion technologies has become a major focus of scientific and engineering efforts.Hydrogen energy is regarded as one of the most promising alternative energy sources due to its high energy density,zero carbon emissions,and sustainability.Electrochemical water splitting produces high-purity hydrogen with minimal CO2 emissions,making it an environmentally friendly hydrogen production method.However,the commercial application of this technology still highly depends on efficient and stable electrocatalysts to reduce the overpotential of the hydrogen evolution reaction(HER)and improve energy conversion efficiency.Although platinum(Pt)-based catalysts exhibit excellent HER activity,their high cost and limited availability restrict large-scale application.Therefore,developing non-precious metal electrocatalysts with high activity,stability,and low cost has become a key research priority.Among various candidate materials,molybdenum carbide shows promising potential to replace Pt due to its Pt-like d-band electronic structure and good electrical conductivity,demonstrating excellent HER performance across a wide pH range.Nevertheless,challenges such as overly strong hydrogen intermediate(H*)adsorption,active site blockage,limited surface area,and insufficient long-term stability hinder its practical application.This review systematically summarizes recent advances in molybdenum carbide-based electrocatalysts for HER,focusing on their electronic structure,synthesis methods,performance optimization strategies,and reaction mechanisms.First,the fundamental mechanism of electrocatalytic hydrogen evolution is introduced,and the potential advantages and limitations of molybdenum carbide as an HER catalyst are analyzed based on its crystal and electronic structure.Then,major synthesis strategies for molybdenum carbide are summarized,including high-temperature carbonization and chemical vapor deposition,highlighting the advantages and limitations of each method in controlling morphology,size,and interface structure.Furthermore,modification approaches for enhancing the HER performance of molybdenum carbide are discussed from multiple perspectives,such as electronic structure modulation,interface engineering,and composite construction—specifically through heterojunction formation,heteroatom doping,carbon compositing,and defect engineering.Density functional theory(DFT)calculations are employed to gain deeper insight into the catalytic mechanisms and structure-activity relationships.Finally,future directions for molybdenum carbide-based catalysts are outlined based on current challenges.This review demonstrates that rational structural design and performance optimization can significantly enhance the HER activity and stability of molybdenum carbide-based materials,providing a theoretical and technical foundation for their practical application in electrochemical water splitting.Future research should emphasize the integration of material design and mechanistic studies to facilitate the transition of molybdenum carbide catalysts from laboratory research to industrial application.

Abstract:Power-to-Methane(PtM)technology presents many advantages,including the reduction of CO2 emissions,the storage of intermittent renewable energy,and the use of existing natural gas infrastructure to address the safety challenges of H2 transportation.The CO2 methanation reaction of the PtM process is strongly exothermic,so how to realize the heat coupling between the hydrogen production by electrolysis and the CO2 methanation reaction has become one of the current research hotspots.In order to assess the impact of different electrolytic hydrogen production technologies on the PtM process and to explore the applicability of different PtM technology routes,a comparative analysis of the energy efficiency and economic viability of coupling High Temperature Electrolysis(HTE)and Low Temperature Electrolysis(LTE)with CO2 methanation was carried out.The results indicate that under baseline calculation parameters,the energy conversion efficiency of the HTE methanation route is higher than that of the LTE methanation route.Furthermore,after heat recovery,the HTE methanation route achieves an even higher energy conversion efficiency of up to 85.8%.As energy efficiency improves,costs are optimized.Although the cost of the HTE methanation route(9.41 CNY/m3)is higher than that of the LTE methanation(8.91 CNY/m3),the cost of the HTE methanation route is reduced to 8.23 CNY/m3 after heat recovery,which provides a certain cost advantage over the LTE methanation route.The sensitivity analysis shows that the electricity price is the key factor affecting the production cost.In order to clarify the economic applicability boundary of each technology route,the key point for the impact of electricity price changes on costs was further investigated.The results show that when the electricity price is lower than 0.24 CNY/kWh,the LTE methanation route exhibits a clear cost advantage,while the HTE methanation route with heat recovery demonstrates better economics when the electricity price is higher than 0.24 CNY/kWh.With the continuous improvement of the carbon trading system,carbon reduction technologies such as PtM technologies not only reduce carbon emissions,but also convert environmental benefits into tangible economic gains through carbon market transactions.When the carbon price exceeds 350 CNY/t,the economics of HTE methanation route with heat recovery can be comparable to the coal-based natural gas production.

Abstract:In order to develop efficient non-precious metal catalysts for hydrogen production by ammonia decomposition,the effects of transition metal(Co,Fe,Mn,Cu)doping and chelating agent(citric acid,triammonium citrate)modification on the structure and properties of Ni/La3Ce7Ox were investigated.The results reveal that transition metal doping led to structural degradation of the catalyst,as indicated by increased grain size,reduced specific surface area,and decreased oxygen vacancies,which in turn lead to weakened metal-support interactions.Citric acid modification significantly optimizes the catalyst structure,reducing grain size,enhancing low-temperature reducibility,and increasing oxygen defect concentration.Performance testing demonstrates that the Ni/La3Ce7Ox catalyst,prepared via citric acid addition,exhibits excellent catalytic activity and stability.Under conditions of a gas hourly space velocity of 60 000 mL/(g·h)and a temperature of 550 ℃,the ammonia decomposition conversion and hydrogen production rate reach 57.5%and 39 mmol/(g·min),respectively.Moreover,the catalyst maintains stable activity over a 100 h cycling test.The above results provide valuable insights for the development of cost-effective and high-performance catalysts for ammonia decomposition to hydrogen production.

Abstract:During hydrogen storage in metal hydride hydrogen storage reactors,the low thermal conductivity of the hydrogen storage alloy results in delayed internal heat dissipation,prolonging the hydrogen storage time and limiting its engineering application.To solve the problems of heat and mass transfer limitations and dynamic response lag in existing metal hydride hydrogen storage reactors,this paper focuses on the dynamic hydrogen storage characteristics and structural optimization of the reactor.A numerical model coupling heat and mass transfer with chemical reactions was established,and the dynamic evolution laws of temperature field,pressure field,and hydrogen storage capacity during the hydrogen storage process were obtained.In order to improve the hydrogen storage performance,the method of increasing the thermal conductivity of the hydrogen storage alloy or internally enhancing heat transfer was adopted.This paper designs a new structure of biomimetic honeycomb and spiral tube that only increases the thermal conductivity of the hydrogen storage alloy and enhances heat transfer inside the reactor,and conducts optimization design research on the structure of the hydrogen storage reactor.The research results show that the new structure of the hydrogen storage reactor proposed in this paper has excellent hydrogen storage performance:compared with the alloy with a thermal conductivity of 12 W/(m·K),the hydrogen storage time for 90%is shortened by less than 50%.Compared to infrastructure,the time required for 90%hydrogen storage has decreased by approximately 84%;As the convective heat transfer coefficient inside the spiral tube increases significantly,it approaches saturation when the flow velocity exceeds 1 m/s;As the thermal conductivity of the honeycomb partition increases,it steadily improves,but the magnitude of the increase is relatively small;Under varying initial temperature and hydrogen supply pressure conditions,the hydrogen storage performance remains stable at 84%without degradation.The new structural design of the hydrogen storage reactor significantly shortens the thermal conductivity distance while providing a larger heat exchange area and internal cooling source.This study provides theoretical basis and technical support for the engineering design and performance improvement of metal hydride hydrogen storage reactors,which is of great significance for promoting the large-scale application of hydrogen energy.

Abstract:Hydrogen embrittlement(HE)is a critical materials-failure issue in hydrogen-containing environments encountered in modern chemical and energy-processing industries.Its intrinsic complexity spans a multiscale cascade—from atomic-level events to macroscopic fracture—and directly threatens the safety and service life of hydrogen-energy infrastructure and chemical-plant equipment.Yet a comprehensive,multiscale review that integrates the full spectrum of HE research in metallic materials remains lacking.This review adopts a multiscale framework to synthesise current understanding of HE phenomena and mechanisms and to identify future research priorities.At the macroscale,we examine how operational parameters such as hydrogen blending ratio,temperature,humidity and applied stress synergistically influence HE susceptibility,highlighting their nonlinear coupling in governing failure behaviour.At the mesoscale,we show how grain size,grain-boundary character and phase-interface morphology regulate hydrogen diffusion,segregation and crack initiation,demonstrating that mesostructural features dictate hydrogen distribution and preferred damage sites.At the microscale,we analyse the interactions between hydrogen atoms and lattice defects—including dislocations,grain boundaries,twin boundaries and nano-precipitates—to clarify the atomic origins of embrittlement through hydrogen trapping,transport and accumulation.Building on insights across these scales,we propose an integrated micro-atomic → meso-interface → macro-crack framework that links cross-scale phenomena to reveal the chain-transfer mechanism of hydrogen-induced failure under coupled multiphysical fields.This unified perspective establishes a continuous failure pathway from local hydrogen enrichment to mesostructural evolution and ultimately to macroscopic crack propagation.Grounded in this multiscale overview,the work provides essential theoretical guidance for the design and optimisation of hydrogen-resistant materials and for safety assessment and lifetime prediction of hydrogen-energy systems operating in hydrogen-bearing environments.

Abstract:In recent years,with the growing global attention to low-carbon economies and energy transitions,hydrogen energy has become a key component of national energy strategies due to its high energy density and zero-emission characteristics.Compared with physical hydrogen storage technologies,chemical hydrogen storage has become a major focus of hydrogen energy research because it can provide higher hydrogen density and more stable storage processes at ambient temperature and pressure.This paper reviews the research progress of chemical hydrogen storage materials,focusing on two main technologies:metal hydride hydrogen storage and organic liquid hydrogen storage.It explores their hydrogen storage mechanisms,performance optimization,and sustainable development pathways.The paper is divided into the following sections:Progress in metal hydride hydrogen storage technology,which includes the performance optimization of different metal hydride storage materials,reactor optimization design,and their economic and environmental impact assessments;The current status of organic liquid hydrogen storage technology,which discusses the selection of organic liquid hydrogen storage materials,catalyst optimization,and their economic and environmental impacts;Other chemical hydrogen storage technologies and methods,including modified carbon materials for chemical adsorption hydrogen storage,the integration of chemical hydrogen storage with solid oxide fuel cells,and the combination of chemical hydrogen storage with green hydrogen production technologies.Through an in-depth comparison and analysis of these technologies,this paper aims to provide theoretical support for the optimization and application of chemical hydrogen storage technologies in the future,and offer references for the sustainable development of hydrogen energy.

Abstract:Photocatalytic water splitting for hydrogen production has attracted significant attention in the field of clean energy due to its green,renewable,and environmentally friendly characteristics.As the core of the reaction,the physicochemical properties of photocatalysts directly determine the efficiency and feasibility of photocatalytic hydrogen evolution.Oxide semiconductors have emerged as an important class of materials for photocatalytic hydrogen production because of their high structural stability,simple preparation process,low cost,and tunable chemical properties.However,their limited visible-light response,rapid recombination of photogenerated electron-hole pairs,and sluggish surface reaction kinetics significantly restrict their practical performance.Therefore,effective structural and performance modulation strategies are urgently required to enhance their light-harvesting capacity,carrier separation efficiency,and surface catalytic activity.This review systematically summarizes recent advances in performance modulation strategies for oxide semiconductor photocatalysts in hydrogen production,with a focus on the mechanisms and optimization effects of three representative approaches.Surface engineering effectively increases the number of light absorption sites and reactive active sites,and regulates the surface energy level structure by means of constructing specific defects,introducing surface plasmon effects,depositing cocatalysts,and so on.Interface engineering uses heterostructure design to realize interface energy band matching and built-in electric field regulation,thereby promoting the directional migration and spatial separation of photogenerated carriers while maintaining strong redox capability.Polarization engineering utilizes the polarization fields generated by piezoelectric or ferroelectric materials under external stress or temperature variation to establish a stable intrinsic potential gradient,effectively controlling carrier distribution and reaction pathways.By analyzing the fundamental principles and representative studies of these modulation strategies,this work summarizes their respective advantages and limitations in enhancing visible-light utilization,extending carrier lifetimes,and improving hydrogen evolution rates.It also highlights current challenges,including the difficulty of precise interfacial control,insufficient defect tunability,and limited long-term stability.Finally,future research directions are proposed,such as synergistic multi-strategy design,in situ characterization combined with theoretical calculations,and pilot-scale and engineering application exploration,to accelerate the development of oxide semiconductor photocatalysts toward high-efficiency,stable,and scalable hydrogen production systems.

Abstract:Hydrogen energy,as a clean and efficient renewable energy source,is regarded as an important component of the future energy system.Among various hydrogen production methods,electrolysis of water to produce hydrogen has attracted widespread attention due to its advantages such as high hydrogen purity and zero carbon emissions.However,the large-scale application of water electrolysis remains constrained by the sluggish kinetics,high overpotentials,and stability issues of the hydrogen evolution reaction(HER)and oxygen evolution reaction(OER).High-entropy alloys,characterized by their multi-element synergy,corrosion resistance,and structural stability,demonstrate substantial potential in electrocatalytic water splitting.Herein,PtPdCoNiCu high-entropy alloys catalysts are investigated to elucidate the interplay between wettability,conductivity,and bubble dynamics during water electrolysis.Surface modifications are implemented to optimize catalytic performance.A quantitative relationship is established between catalyst surface hydrophilicity,electrical conductivity,bubble behavior,and electrocatalytic efficiency.Experimental results demonstrate that enhanced surface wettability promotes bubble detachment and improves HER kinetics,while increased conductivity accelerates electron transfer and reduces HER overpotentials.Novel insights and experimental evidence for designing high-performance electrocatalysts through surface property optimization are provided.

Abstract:As the global energy system transitions toward low-carbon and clean energy,utilizing hydrogen for power generation and producing and storing hydrogen through water electrolysis has gradually become a key approach to reducing dependence on fossil fuels and accelerating the transformation of power grids toward new energy.Hydrogen production and power generation units are key components in this system,with their performance,stability,and lifespan directly impacting the overall efficiency and application prospects of the hydrogen energy industry chain.Proton exchange membrane fuel cell power generation and water electrolysis hydrogen production technologies hold promising prospects,but cost and durability remain areas requiring improvement,limiting their further commercialization.First,it briefly describes the advantages of hydrogen production and power generation based on proton exchange membrane technology compared to other methods.Subsequently,the failure mechanisms and diagnostic methods for proton exchange membrane electrolysis cells are elaborated.For typical failures such as membrane degradation and flow field blockage,the causes of different failures are analyzed.The impact on critical components within equipment and corresponding mitigation measures are addressed.Model-based and data-driven fault diagnosis methods are reviewed,comparing the principles,research outcomes,and advantages and disadvantages of different diagnostic approaches.Then,the working principle of proton exchange membrane fuel cells was outlined,and the mechanisms behind typical flooded and membrane dry failures were analyzed,along with their impact on equipment.The latest advances in fault diagnosis methods for proton exchange membrane fuel cells are reviewed,comparing the principles,research outcomes,and advantages and disadvantages of test-based,model-based,and data-based diagnostic approaches.Finally,future development directions are proposed across four dimensions:fault mechanism and model establishment,online diagnosis and multi-fault classification,fault mitigation and control strategy optimization,and integrated advancement.These include:constructing multi-physics mechanism models for diagnostics that incorporate aging patterns;developing online diagnostic methods adapted to actual operating conditions to enhance composite fault recognition capabilities;optimizing control and mitigation strategies to achieve adaptive regulation;Leveraging established fuel cell expertise to develop diagnostic systems tailored to electrolyzer characteristics,thereby enhancing overall system reliability.

Abstract:The shuttle effect induced by the dissolution of polyiodides constitutes a critical challenge constraining the performance of zinc-iodine batteries(Zn-I2).As one of the vital electrode materials for Zn-I2 batteries,the pore structure and surface chemical composition of porous carbon materials significantly influence the performance of Zn-I2 batteries.In this study,a hundred-gram-scale ZIF-8@ZnO composite was synthesized via mechanical ball-milling using nano-ZnO as both a structural template and metal ion source.Serving as carbon precursors,these composites were subjected to high-temperature pyrolysis,leveraging the physical confinement effect of nano-ZnO and the inherent microporosity/nitrogen-rich characteristics of ZIF-8,to obtain nitrogen-doped porous carbons(denoted as NC-x,where x represents the pyrolysis temperature)featuring co-existing mesopores and micropores.The NC-x materials were applied as cathodes in aqueous Zn-I2 batteries,and systematic investigations were conducted to elucidate the influence of pore architecture and nitrogen doping configurations on battery performance.Specifically,mesopores shortened the diffusion pathways of the KI electrolyte and effectively confined polyiodide intermediates,while micropores facilitated strong adsorption of I-ions and suppressed I3-formation.Graphitic nitrogen within the carbon framework significantly enhanced electrical conductivity,whereas pyridinic and pyrrolic nitrogen species acted as chemisorption sites to strengthen interactions between iodine species and the carbon matrix,thereby effectively mitigating the shuttle effect.Benefiting from optimal pore structure,N-doping types and percentage of atomic quantity,NC-1000 exhibits superior electrochemical performance:high capacity(248.6 mAh/g at 1 A/g),outstanding rate capability(86.1 mAh/g retained at 20 A/g),and exceptional cycling stability(90%capacity retention after 16 000 cycles at 10 A/g).In conclusion,rational pore design and surface composition regulation significantly enhance the performance of porous carbon-based Zn-I2 batteries.

Abstract:With the continuous acceleration of global industrialization,the conflict between energy supply and demand has intensified.The excessive consumption of traditional fossil fuels not only triggers resource depletion crises but also causes severe environmental issues.Consequently,the development and utilization of sustainable energy sources have emerged as a globally recognized core pathway to resolving the energy crisis.Among various energy conversion technologies,photocatalysis has emerged as a prominent research hotspot in the energy and materials fields in recent years.This technology offers a highly innovative solution for transforming and upgrading energy structures by directly converting clean,renewable solar energy into stable,high-energy-density chemical fuels—such as hydrogen and hydrocarbon fuels.Cu-based quantum dots(QDs),as a novel class of semiconductor nanomaterials,have gained prominence in photocatalysis owing to their unique advantages,including quantum size effects,tunable light absorption properties,and high charge carrier mobility.Furthermore,compared to traditional precious metal-based catalytic materials,Cu-based QDs benefit from eco-friendliness,abundant raw material reserves,and low cost,making them better aligned with the practical requirements of large-scale applications.Consequently,they demonstrate irreplaceable and broad application prospects in the field of photocatalysis.This review systematically summarizes recent research advances in Cu-based QDs for photocatalytic solar-to-fuel conversion.First,it outlines the fundamental properties of quantum dots,focusing on their defining features such as quantum size effects and surface effects,along with the most widely employed preparation methods including sol-gel,hot-injection,and hydrothermal synthesis.Second,Cu-based QDs are categorized and discussed based on their chemical composition,encompassing Cu QDs,alloy QDs,oxide QDs,sulfide QDs,and selenide QDs.Building upon this foundation,the application mechanisms and advancements of Cu-based QDs in photocatalytic energy conversion fields—including water splitting for H2 production,photocatalytic H2O2 generation,and photocatalytic reduction of CO2 to produce hydrocarbon fuels—have been summarized.Finally,future trends and prospects for Cu-based QDs in solar fuel conversion are discussed.This review is expected to provide valuable insights into the rational design and performance optimization of Cu-based QDs photocatalysts and offer some theoretical foundation and experimental guidance for expanding their practical applications in sustainable energy transformation systems.

Abstract:Hydrogen energy,as a clean,efficient and sustainable energy source,holds an important position in the current context of energy transition and sustainable development.However,there are still problems such as high production cost,difficult storage and transportation,insufficient infrastructure and significant safety challenges in the use of hydrogen energy.Among them,the storage and transportation of hydrogen are the core links in the utilization of hydrogen energy and have received extensive attention.Among various hydrogen storage methods,magnesium-based solid-state hydrogen storage materials can stably store hydrogen at normal temperature and pressure,greatly reducing the requirements for auxiliary equipment and safety risks,which hold broad application prospects.However,magnesium-based hydrogen storage alloys have high temperatures and slow kinetics during hydrogen absorption and desorption processes,which to some extent limit the application range of magnesium-based hydrogen storage materials.The addition of elements such as Ni,La and Mn can effectively improve the performance of Mg-based hydrogen storage materials.However,the dehydrogenation temperature and reaction kinetics mechanism of Mg-Ni-La-Mn hydrogen storage alloys are still unclear.To obtain the desorption reaction kinetics characteristics of Mg-Ni-La-Mn hydrogen storage alloys,this paper first prepared Mg-Ni-La-2Mn hydrogen storage alloys by induction melting method.Then,an experimental system was built to test the dehydrogenation kinetics performance of Mg-Ni-La-2Mn hydrogen storage alloys.Subsequently,based on the experimental results,the Johnson-Mehl-Avrami(JMA)kinetics equation and the dehydrogenation kinetics Arrhenius curve of Mg-Ni-La-2Mn hydrogen storage alloys were obtained.Finally,the kinetics equation of hydrogen dehydrogenation in Mg-Ni-La-2Mn hydrogen storage alloy was compiled into the Comsol software for numerical simulation to verify the reliability of the obtained JMA kinetics equation and Arrhenius curve.The dehydrogenation experiments of Mg-Ni-La-2Mn showed that when the dehydrogenation temperature was above 553 K,the alloy could achieve complete desorption within 2 400 s.Increasing the desorption temperature could accelerate the desorption rate and reduce the desorption time.When the dehydrogenation temperature is 593 K,the maximum dehydrogenation amount and the time required for 80%dehydrogenation of the alloy sample were 6.19%(weight percentage)and 232 s,respectively.By analyzing the JMA equation and Arrhenius curve of Mg-Ni-La-2Mn alloy,the activation energy in the dehydrogenation process was found to be 66.67 kJ/mol,which was much lower than the values reported in the literature.The dehydrogenation process of Mg-Ni-La-2Mn alloy was numerically simulated and compared with the experimental data.The maximum error of hydrogen desorption amount was 2.81%,and the maximum relative error of temperature was only 0.04%,verifying the reliability of the established dehydrogenation reaction kinetics equation of Mg-Ni-La-2Mn hydrogen storage alloy.

Abstract:Solar energy-driven photocatalytic H2 production,as a key technology in the clean conversion and utilization of energy field,has the potential to achieve efficient utilization of solar energy and low-cost green H2 production,and has been paid extensive attention.Until now,although the research methods based on traditional empirical trial-and-error have realized enhanced photocatalytic efficiencies for H2 production that are far from meeting the required efficiency of industrial application,severely restricting its future large-scale application.Machine learning,by establishing a data-driven intelligent analysis paradigm,is driving the field of photocatalytic H2 production to shift from the traditional trial-and-error based on experience to a research model of precise prediction,and expected to promote the breakthroughs in photocatalytic H2 production.Accordingly,this paper systematically reviews the applications and research progress of machine learning in photocatalytic H2 production:Firstly,the core elements of the machine learning technology framework are explained,with a particular focus on the construction strategy of the photocatalysis dataset and the optimization path of feature engineering(covering physical-chemical descriptor screening,high-dimensional feature dimension reduction,and knowledge embedding methods,etc.).Secondly,the application of machine learning in the field of photocatalysis is discussed.In terms of optimizing material performance,a systematic summary is provided of the breakthroughs made by machine learning in key aspects such as precise regulation of band structure,improvement of carrier migration efficiency,and intelligent design of interface heterojunctions.At the level of experimental process innovation,the focus is on exploring dynamic parameter optimization algorithms based on machine learning,intelligent high-throughput experimental platforms,and adaptive model construction with real-time feedback capabilities.Finally,it is proposed that the future development of machine learning in this field should focus on building a new research paradigm driven by both data and mechanism,developing interpretable models with physical constraints,and constructing cross-scale dynamic simulation systems.Ultimately,it will provide full-chain intelligent optimization for the research and development of photocatalytic hydrogen production technology,from microscopic mechanisms to macroscopic processes.

Abstract:Graphitic carbon nitride(g-C3N4),a metal-free semiconductor featuring a unique band structure and excellent chemical stability,has attracted increasing attention in the field of antimicrobial materials in recent years.In the context of escalating bacterial infections,the rapid proliferation of drug-resistant pathogens,and the declining efficacy of conventional antibiotics,the development of novel antimicrobial technologies that are efficient and less prone to inducing resistance has become an urgent necessity.Antibacterial strategies based on photocatalysis and nanozyme-like catalysis offer new solutions to these challenges.Among them,g-C3N4-based material systems show remarkable potential across multiple antibacterial scenarios due to their tunable structure,high specific surface area,strong visible-light response,and good biocompatibility.The antibacterial mechanisms and application progress of g-C3N4-based materials are systematically summarized in this review.First,from a structural perspective,the layered framework of g-C3N4,its abundant surface nitrogen functionalities,and its electronically adjustable characteristics-achieved via doping,heterojunction construction,and defect engineeringare introduced.The charge-carrier separation efficiency and catalytic reactivity are significantly improved,forming the basis for high-performance antibacterial functionality.Regarding antibacterial mechanisms,this review outlines the multiple bactericidal pathways of g-C3N4-based materials.Their sheet-like structure can induce physical damage to bacterial cell walls,producing a certain degree of contact-based antibacterial action.Under light irradiation,g-C3N4 generates electron-hole pairs that participate in redox reactions,leading to the formation of reactive oxygen species(ROS).These ROS disrupt cell membrane integrity and oxidize proteins,representing the core of g-C3N4-based photocatalytic antibacterial activity.Some metal-loaded or structurally modified g-C3N4 systems exhibit enzyme-mimicking catalytic behavior,simulating peroxidase-or oxidase-like activities and further enhancing antibacterial efficiency.The synergistic interplay of these mechanisms not only improves bactericidal performance but also reduces the likelihood of resistance development.In terms of practical applications,the advancements in four major areas are highlighted in this review:water purification,air disinfection,biomedical anti-infection,and functional antibacterial coatings.In water treatment,g-C3N4 enables efficient inactivation of waterborne pathogens under visible light and can be integrated with filtration membranes or adsorbents to construct continuous-flow disinfection systems.In air purification,g-C3N4-based catalytic filter layers effectively suppress airborne bacterial and viral transmission.In biomedical applications,g-C3N4 nanomaterials,benefiting from photodynamic or photothermal enhancement,are used for wound sterilization,implant-associated infection prevention,and skin regeneration.For antibacterial coatings,incorporating g-C3N4 into polymeric,metallic,or ceramic substrates yields durable,renewable,and environmentally friendly antimicrobial surfaces.Finally,the current advances and identifies future challenges are summarized in this review,including improving charge-carrier utilization,clarifying biosafety profiles,further elucidating multi-mechanism synergistic effects,and advancing large-scale material fabrication.

Abstract:To investigate the influence of electricity market mechanisms and ancillary service subsidies on the operational optimization of electricity-hydrogen systems,this study develops an hourly power-net profit optimization model.A 100 MW alkaline electrolyzer system,composed of twenty 5 MW units,is selected as the case study.The model integrates time-of-use electricity pricing,ancillary service subsidies,and parameter sensitivity analysis within a coordinated electricity-hydrogen coupling framework.Three scenarios—valley,mid-level,and peak pricing—are designed to quantify the electricity market effects on hydrogen production strategies.The nonlinear adjustment effects of ancillary service subsidies on system profitability are analyzed.The results show that time-of-use pricing significantly directs the optimal dispatch:under valley pricing,breakeven is achieved at 14%rated hydrogen production power and net revenue peaks at full power load;under mid-level pricing,the system operates all at a loss with an optimal load power of 63%;under peak pricing,the system minimizes loss by operating at 8%power.Ancillary service subsidies introduce nonlinear optimistic impacts on dispatch decisions:at 0.1  CNY/kWh,the system breaks even under both mid and peak pricing scenarios via load adjustment;at 0.2-0.4  CNY/kWh,the optimal strategy shifts from hydrogen production-oriented to ancillary service-oriented,reducing the optimal load to 21%in valley scenarios.Sensitivity analysis indicates that green hydrogen prices have a greater influence on optimization outcomes than fixed costs.While fixed costs linearly affect net profits,hydrogen prices introduce nonlinear effects,partially mitigated by subsidy mechanisms.This study reveals the coupling mechanisms between electricity market signals and service subsidies in electricity-hydrogen optimization,offering a technical basis for hydrogen system dispatch strategies and electricity market design.