Integrating electrochemical upgrading of glycerol and water electrolysis is regarded as a promising and energy-saving approach for the co-production of chemicals and hydrogen.However,developing efficient electrocataly...Integrating electrochemical upgrading of glycerol and water electrolysis is regarded as a promising and energy-saving approach for the co-production of chemicals and hydrogen.However,developing efficient electrocatalyst towards this technology remains challenging.Herein,a metallic cobalt mediated molybdenum nitride heterostructural material has been exploited on nickel foam(Co@Mo_(2)N/NF)for the glycerol oxidation reaction(GOR)and hydrogen evolution reaction(HER).Remarkably,the obtained Co@Mo_(2)N/NF realizes eminent performance with low overpotential of 49 mV at 50 mA/cm^(2)for HER and high Faradaic efficiency of formate of 95.03%at 1.35 V vs.RHE for GOR,respectively.The systematic in-situ experiments reveal that the Co@Mo_(2)N heterostructure promotes the cleavage of C-C bond in glycerol by active CoOOH species and boosts the conversion of glycerol to aldehyde intermediates to formate product.Moreover,the density functional theory(DFT)calculations confirm the strong interaction at Co@Mo_(2)N interface,which contributes to the optimized water dissociation and the transformation of H^(*)to H^(2).Benefiting from those advantages,the built HER||GOR electrolyzer delivers a low voltage of 1.61 V at 50 mA/cm^(2),high Faradaic efficiency,and robust stability over 120 h for sustained and stable electrolysis.展开更多
Urgent requirements of the renewable energy boost the development of stable and clean hydrogen,which could effectively displace fossil fuels in mitigating climate changes.The efficient interconversion of hydrogen and ...Urgent requirements of the renewable energy boost the development of stable and clean hydrogen,which could effectively displace fossil fuels in mitigating climate changes.The efficient interconversion of hydrogen and electronic is highly based on polymer electrolyte membrane fuel cells(PEMFCs)and water electrolysis(PEMWEs).However,the high cost continues to impede large-scale commercialization of both PEMFC and PEMWE technologies,with the expense primarily attributed to noble catalysts serving as a major bottleneck.The reduction of Pt loading in PEMFCs is essential but limited by the oxygen transport resistance in the cathode catalyst layers(CCLs),while the oxygen transport in anode catalyst layers(ACLs)in PEMWEs also being focused as the Ir/IrO_(x) catalyst reduced.The pore structure and the catalyst-ionomer agglomerates play important roles in the oxygen transport process of both PEMFCs and PEMWEs due to the similarity of membrane electrode assembly(MEA).Herein,the oxygen transport mechanism of PEMFCs in pore structure and ionomer thin films in CCLs is systematically reviewed,while state-of-the-art strategies are presented for enhancing oxygen transport and performance through materials and structural design.The deeply research opens avenues for exploring similar key scientific problems in oxygen transport process of PEMWEs and their further development.展开更多
Seawater electrolysis for hydrogen production faces inherent challenges, including side reactions, corrosion, and scaling, stemming from the intricate composition of seawater. In response, researchers have turned to c...Seawater electrolysis for hydrogen production faces inherent challenges, including side reactions, corrosion, and scaling, stemming from the intricate composition of seawater. In response, researchers have turned to continuous water splitting using forward osmosis(FO)-driven seawater desalination. However, the necessity of a neutral electrolyte hampers this strategy due to the limited current density and scarcity of precious metals. Herein, this study applies alkali-durable FO membranes to enable self-sustaining seawater splitting, which can selectively withdraw water molecules, from seawater, via concentration gradient. The membranes demonstrates outstanding perm-selectivity of water/ions(~5830 mol mol^(-1)) during month-long alkaline resistance tests, preventing electrolyte leaching(>97% OHàretention) while maintaining ~95%water balance(V_(FO)= V_(electrolysis)) via preserved concentration gradient for consistent forward-osmosis influx of water molecules. With the consistent electrolyte environment protected by the polyamide FO membranes, the Ni Fe-Ar-P catalyst exhibits promising performance: a sustain current density of 360 m A cmà2maintained at the cell voltage of 2.10 V and 2.15 V for 360 h in the offshore seawater, preventing Cl/Br corrosion(98% rejection) and Mg/Ca passivation(99.6% rejection). This research marks a significant advancement towards efficient and durable seawater-based hydrogen production.展开更多
Production of green hydrogen through water electrolysis powered by renewable energy sources has garnered increasing attention as an attractive strategy for the storage of clean and sustainable energy.Among various ele...Production of green hydrogen through water electrolysis powered by renewable energy sources has garnered increasing attention as an attractive strategy for the storage of clean and sustainable energy.Among various electrolysis technologies,the emerging anion exchange membrane water electrolyser(AEMWE)exhibits the most potential for green hydrogen production,offering a potentially costeffective and sustainable approach that combines the advantages of high current density and fast start from proton exchange membrane water electrolyser(PEMWE)and low-cost catalyst from traditional alkaline water electrolyser(AWE)systems.Due to its relatively recent emergence over the past decade,a series of efforts are dedicated to improving the electrochemical reaction performance to accelerate the development and commercialization of AEMWE technology.A catalytic electrode comprising a gas diffusion layer(GDL)and a catalyst layer(CL)is usually called a gas diffusion electrode(GDE)that serves as a fundamental component within AEMWE,and also plays a core role in enhancing mass transfer during the electrolysis process.Inside the GDEs,bubbles nucleate and grow within the CL and then are transported through the GDL before eventually detaching to enter the electrolyte in the flow field.The transfer processes of water,gas bubbles,charges,and ions are intricately influenced by bubbles.This phenomenon is referred to as bubble-associated mass transfer.Like water management in fuel cells,effective bubble management is crucial in electrolysers,as its failure can result in various overpotential losses,such as activation losses,ohmic losses,and mass transfer losses,ultimately degrading the AEMWE performance.Despite significant advancements in the development of new materials and techniques in AEMWE,there is an urgent need for a comprehensive discussion focused on GDEs,with a particular emphasis on bubbleassociated mass transfer phenomena.This review aims to highlight recent findings regarding mass transfer in GDEs,particularly the impacts of bubble accumulation;and presents the latest advancements in designing CLs and GDLs to mitigate bubble-related issues.It is worth noting that a series of innovative bubble-free-GDE designs for water electrolysis are also emphasized in this review.This review is expected to be a valuable reference for gaining a deeper understanding of bubble-related mass transfer,especially the complex bubble behavior associated with GDEs,and for developing innovative practical strategies to advance AEMWE for green hydrogen production.展开更多
The commercialization of proton exchange membrane water electrolysis(PEMWE)for green hydrogen production hinges on the development of low-cost,high-performance titanium porous transport layers(PTLs).This study introdu...The commercialization of proton exchange membrane water electrolysis(PEMWE)for green hydrogen production hinges on the development of low-cost,high-performance titanium porous transport layers(PTLs).This study introduces a triple-layer Ti-PTL with a graded porous structure and a 75%ultra-high porosity backing layer,fabricated through tape casting and roll calendering.This triple-layer PTL,composed of a microporous layer,an interlayer,and a highly porous backing layer,enhances catalyst utilization,mechanical integrity,and mass transport.Digital twin technology using X-ray revealed increased contact area and triple-phase boundary at the interface with the catalyst layer,significantly improving oxygen evolution reaction kinetics.Numerical simulations demonstrated that the strategically designed porous structure of the triple-layer PTL facilitates efficient oxygen transport,mitigates oxygen accumulation,and improves reactant accessibility.Electrochemical evaluations showed improved performance,achieving 127 mV reduction in voltage at 2 A cm^(-2)compared to a commercial PTL,highlighting its potential to enhance PEMWE efficiency and cost-effectiveness.展开更多
Atomically dispersed metal site(ADMS)materials have emerged as a promising class of materials for electrocatalysis reactions in the field of energy conversion.Characterized by individual metal atoms dispersed on suita...Atomically dispersed metal site(ADMS)materials have emerged as a promising class of materials for electrocatalysis reactions in the field of energy conversion.Characterized by individual metal atoms dispersed on suitable supports,ADMS materials provide unique catalytic sites with highly tunable electronic structures.This review summarizes recent advancements in the field,with a focus on the critical roles of support materials,coordination environments,and the mechanisms underlying catalytic activity at the atomic level.First,commonly used density functional theory(DFT)simulations are reviewed,emphasizing their pivotal role in elucidating reaction mechanisms and predicting the behavior of ADMS in electrochemical reactions for hydrogen energy utilization.Then,advancements in ADMS for half-cell electrochemical reactions,including oxygen evolution reaction,hydrogen evolution reaction,and oxygen reduction reaction,as well as their applications in fuel cells and water splitting,are summarized.Finally,the challenges and future prospects of ADMS are discussed.This review underscores the transformative potential of ADMS in electrocatalysis,paving the way for innovative and sustainable energy conversion technologies.展开更多
Bifunctional Ir catalysts for proton exchange membrane(PEM)water electrolysis offer transformative potential by streamlining electrolyzer while achieving efficient performance remains challenging due to the distinct c...Bifunctional Ir catalysts for proton exchange membrane(PEM)water electrolysis offer transformative potential by streamlining electrolyzer while achieving efficient performance remains challenging due to the distinct conditions required for oxygen and hydrogen evolution reaction(OER and HER).Herein,we propose a theory-directed design of Ir-based bifunctional catalysts,Ir nanoparticles supported on mesoporous carbon spheres embedded with MoSe_(2)(Ir/MoSe_(2)@MCS),leveraging a work function(WF)-induced spontaneous built-in electric field to enhance catalytic performance.They demonstrate exceptional kinetics for both OER and HER,and potential application in the practical PEM electrolyzer,showcasing the effectiveness of this innovative approach.Low overpotentials of 252 mV for OER and 28 mV for HER to drive 10 mA cm^(-2)were observed,and the PEM electrolyzer showed the current density of 2 A cm^(-2)at 1.87 V and maintained stable activity at 1.65 V for over 30 h to deliver 1 A cm^(-2).Density functional theory calculations reveal that the WF difference at Ir/MoSe_(2)interface induces a spontaneous built-in electric field with asymmetric charge distributions,that modulate the electronic environment and d-band center of Ir promoting bifunctional active phase formation.This significantly lowers reaction barriers for water splitting by balancing intermediate adsorption,endowing the bifunctional activity.展开更多
Optimizing the energy barrier of 2H-to-1T phase transformation plays a crucial role in modulating the intrinsic electronic structure of MoS_(2)to achieve satisfactory water-splitting performance,but remains a signific...Optimizing the energy barrier of 2H-to-1T phase transformation plays a crucial role in modulating the intrinsic electronic structure of MoS_(2)to achieve satisfactory water-splitting performance,but remains a significant challenge.Herein,we report a vacancy occupation-triggered phase transition strategy to fabricate a core-shell 1T phase nanorod structure,which is composed of S-vacancies decorated MoS_(2)as the core,and N,P co-doped carbons as the shell(1T-MoS_(2)@NPC).The co-insertion of N and P dopants into MoS_(2)can occupy partial S-vacancies,triggering a phase transformation from the semiconducting 2H phase to the conducting 1T phase with a reduced energy barrier.Profiting from the strong coupling effect between N,P dopants and S-vacancies,the as-made 1T-MoS_(2)@NPC exhibits excellent electrocatalytic activity for both HER(η_(10)=148 m V)and OER(η_(10)=232 mV)in alkaline solution.Meanwhile,a low cell voltage of 1.62 V is needed to drive a current density of 10mA cm^(-2)in 1.0 M KOH electrolyte.The theoretical calculation results reveal that the S-vacancies decorated C atoms in the meta-position relative to N,P atoms represent the most active HER and OER sites,which synergistically upshift the d band center and balance the rate-determining step,thus ensuring the simultaneous optimization of adsorption free energy and electronic structure.This vacancy-occupation-derived phase transformation strategy caused by non-metallic doping may provide valuable guidance for enhancing the performance of alkaline water electrolysis.展开更多
Since the beginning of the 20th century,alkaline electrolysis has been used as a proven method for producing hydrogen on a megawatt scale.The existence of parasitic shunt currents in alkaline water electrolysis,which ...Since the beginning of the 20th century,alkaline electrolysis has been used as a proven method for producing hydrogen on a megawatt scale.The existence of parasitic shunt currents in alkaline water electrolysis,which is utilized to produce clean hydrogen,is investigated in this work.Analysis has been done on a 20-cell stack.Steel end plates,bipolar plates,and an electrolyte concentration of 6 M potassium hydroxide are all included in the model.The Butler-Volmer kinetics equations are used to simulate the electrode surfaces.Ohmic losses are taken into consideration in both the electrode and electrolyte phases,although mass transport constraints in the gas phase are not.Using an auxiliary sweep to solve equations,the model maintains an isothermal condition at 85℃ while adjusting the average cell voltage between 1.3 and 1.8 V.The results show that lower shunt currents in the outlet channels as opposed to the intake channels are the result of the electrolyte’s lower effective conductivity in the upper channels,which is brought on by a lower volume fraction of the electrolyte.Additionally,it has been seen that the shunt currents intensify as the stack gets closer to the conclusion.Efficiency is calculated by dividing the maximum energy output(per unit of time)that a fuel cell operating under comparable conditions might produce by the electrical energy needed to generate that output inside the stack.At first,energy efficiency increases due to the rise in coulombic efficiency,peaking around 1400 mA.The subsequent decline after reaching 1400 mA is linked to an increase in stack voltage at elevated current levels.展开更多
Despite the cost and activity advantages,ruthenium-based oxygen evolution reaction(OER)catalysts face severe stability problems for proton exchange membrane water electrolysis(PEM-WE)due to Ru dissolution.Although tre...Despite the cost and activity advantages,ruthenium-based oxygen evolution reaction(OER)catalysts face severe stability problems for proton exchange membrane water electrolysis(PEM-WE)due to Ru dissolution.Although tremendous attention has been paid to enhancing the stability and activity under small current density in three electrode systems,there still lacks validation under industrial current density at the device level.Aiming at this issue,we report highly active and durable ruthenium-iridium alloyed oxides(IrRuO_(x))as the acidic OER catalyst for PEM-WE with exceptional durability for 1600 h at an industrial current density of 2.0 A·cm^(−2).X-ray absorption spectroscopy reveals that the introduction of iridium modulates the electronic structure of Ru and strengthens the local Ru–O bonds in RuO_(2),which is crucial for ensuring activity and stability.As a result,in comparison with its RuO_(2) counterpart,IrRuO_(x) works stably against the Ru leaching-induced catalytic layer breakage during the stability test.This work demonstrates the great potential of IrRuO_(x) as the practical OER catalyst for the application in PEM-WE.展开更多
The electrocatalytic water-splitting process is widely acknowledged as the most sustainable and environmentally friendly technology for hydrogen(H2)production.However,its energy efficiency is significantly constrained...The electrocatalytic water-splitting process is widely acknowledged as the most sustainable and environmentally friendly technology for hydrogen(H2)production.However,its energy efficiency is significantly constrained by the kinetically slow oxygen evolution reaction(OER)at the anode,which accounts for about 90%of the electrical energy consumption in the water-splitting process.A new strategy is urgently needed to reduce its energy consumption.In recent years,electrochemical oxidation of small molecules has been considered for replacement of OER for efficient H2 production,due to its benign operational conditions,low theoretical thermodynamic potential,high conversion efficiency and selectivity,and environmental sustainability.Hybrid electrolysis systems,by integrating cathodic hydrogen evolution reaction with anodic oxidation of small molecules,have been introduced,which can generate high-purity H2 and produce value-added products or pollutant degradation.In this review,we highlight the recent advancements and significant milestones achieved in hybrid water electrolysis systems.The focus is on non-noble metal electrocatalysts,reaction mechanisms,and the construction of electrolyzers.Additionally,we present the prevailing challenges and future perspectives pertinent to the evolution of this burgeoning technology.展开更多
Green hydrogen produced by water electrolysis combined with renewable energy is a promising alternative to fossil fuels due to its high energy density with zero-carbon emissions.Among water electrolysis technologies,t...Green hydrogen produced by water electrolysis combined with renewable energy is a promising alternative to fossil fuels due to its high energy density with zero-carbon emissions.Among water electrolysis technologies,the anion exchange membrane(AEM) water electrolysis has gained intensive attention and is considered as the next-generation emerging technology due to its potential advantages,such as the use of low-cost non-noble metal catalysts,the relatively mature stack assembly process,etc.However,the AEM water electrolyzer is still in the early development stage of the kW-level stack,which is mainly attributed to severe performance decay caused by the core component,i.e.,AEM.Here,the review comprehensively presents the recent progress of advanced AEM from the view of the performance of water electrolysis cells.Herein,fundamental principles and critical components of AEM water electrolyzers are introduced,and work conditions of AEM water electrolyzers and AEM performance improvement strategies are discussed.The challenges and perspectives are also analyzed.展开更多
Continuous efforts are underway to reduce carbon emissions worldwide in response to global climate change.Water electrolysis technology,in conjunction with renewable energy,is considered the most feasible hydrogen pro...Continuous efforts are underway to reduce carbon emissions worldwide in response to global climate change.Water electrolysis technology,in conjunction with renewable energy,is considered the most feasible hydrogen production technology based on the viable possibility of large-scale hydrogen production and the zero-carbon-emission nature of the process.However,for hydrogen produced via water electrolysis systems to be utilized in various fields in practice,the unit cost of hydrogen production must be reduced to$1/kg H_(2).To achieve this unit cost,technical targets for water electrolysis have been suggested regarding components in the system.In this paper,the types of water electrolysis systems and the limitations of water electrolysis system components are explained.We suggest guideline with recent trend for achieving this technical target and insights for the potential utilization of water electrolysis technology.展开更多
Green hydrogen(H_(2))produced by renewable energy powered alkaline water electrolysis is a promising alternative to fossil fuels due to its high energy density with zero-carbon emissions.However,efficient and economic...Green hydrogen(H_(2))produced by renewable energy powered alkaline water electrolysis is a promising alternative to fossil fuels due to its high energy density with zero-carbon emissions.However,efficient and economic H_(2) production by alkaline water electrolysis is hindered by the sluggish hydrogen evolution reaction(HER)and oxygen evolution reaction(OER).Therefore,it is imperative to design and fabricate high-active and low-cost non-precious metal catalysts to improve the HER and OER performance,which affects the energy efficiency of alkaline water electrolysis.Ni_(3)S_(2) with the heazlewoodite structure is a potential electrocatalyst with near-metal conductivity due to the Ni–Ni metal network.Here,the review comprehensively presents the recent progress of Ni_(3)S_(2)-based electrocatalysts for alkaline water electrocatalysis.Herein,the HER and OER mechanisms,performance evaluation criteria,preparation methods,and strategies for performance improvement of Ni_(3)S_(2)-based electrocatalysts are discussed.The challenges and perspectives are also analyzed.展开更多
Hydrogen is considered as the promising energy carrier to substitute traditional fossil fuel,due to its cleanliness,renewability and high energy density.Water electrolysis is a simple and eonvenient technology for hyd...Hydrogen is considered as the promising energy carrier to substitute traditional fossil fuel,due to its cleanliness,renewability and high energy density.Water electrolysis is a simple and eonvenient technology for hydrogen production.The efficiency of water electrolysis for hydrogen production is limited by the electrocatalytic performances on hydrogen evolution reaction(HER)and oxygen evolution reaction(OER).The exorbitant Pt-and Ir-/Ru-based electrocatalysts as optimal HER and OER electrocatalysts,respectively,restrict water electrolysis development.Recently,non-precious metal-based high-entropy electrocatalysts have exhibited excellent electrocatalytic activities and long-term stabilities for water electrolysis,as promising precious cataly st candidates.Therefore,the construction of the high-entropy electroc atalysts is vital to water electrolysis industry.Electrodeposition technology is an efficient method for the preparation of high-entropy electrocatalysts due to its simple,fast,energy-saving and environmental-friendly advantages.Multi-component co-precipitation facilely occurs during the electroredox in electrodeposition processes.High-entropy alloys,oxides,(oxy)hydroxides,phosphides and phosphorus sulfide oxides have been successfully prepared by galvanostatic,potentiostatic electrodeposition,cyclic voltammetry,pulse,nanodroplet-mediated and cathodic plasma electrodeposition techniques.Hence,introduction of the development of high-entropy electrocatalysts synthesized by electrodeposition technology is significant to researchers and industries.Challenges and outlooks are also concluded to boost the industrial application of electrodeposition in water electrolysis and other energy conversion areas.展开更多
Precisely refining the electronic structure of electrocatalysts represents a powerful approach to further optimize the electrocatalytic performance.Herein,we demonstrate an ingenious d-d orbital hybridization concept ...Precisely refining the electronic structure of electrocatalysts represents a powerful approach to further optimize the electrocatalytic performance.Herein,we demonstrate an ingenious d-d orbital hybridization concept to construct Mo-doped Co_(9)S_(8) nanorod arrays aligned on carbon cloth(CC)substrate(abbreviated as Mo-Co_(9)S_(8)@CC hereafter)as a high-efficiency bifunctional electrocatalyst toward water electrolysis.It has experimentally and theoretically validated that the 4d-3d orbital coupling between Mo dopant and Co site can effectively optimize the H_(2)O activation energy and lower H^(*)adsorption energy barrier,thereby leading to enhanced hydrogen evolution reaction(HER)and oxygen evolution reaction(OER)activities.Thanks to the unique electronic and geometrical advantages,the optimized Mo-Co_(9)S_(8)@CC with appropriate Mo content exhibits outstanding bifunctional performance in alkaline solution,with the overpotentials of 75 and 234 mV for the delivery of a current density of 10 mA cm^(-2),small Tafel slopes of 53.8 and 39.9 mV dec~(-1)and long-term stabilities for at least 32 and 30 h for HER and OER,respectively.More impressively,a water splitting electrolylzer assembled by the self-supported Mo-Co_(9)S_(8)@CC electrode requires a low cell voltage of 1.53 V at 10 mA cm^(-2)and shows excellent stability and splendid reversibility,demonstrating a huge potential for affordable and scalable electrochemical H_(2) production.The innovational orbital hybridization strategy for electronic regulation herein provides an inspirable avenue for developing progressive electrocatalysts toward new energy systems.展开更多
The increasing demand for hydrogen energy to address environmental issues and achieve carbon neutrality has elevated interest in green hydrogen production,which does not rely on fossil fuels.Among various hydrogen pro...The increasing demand for hydrogen energy to address environmental issues and achieve carbon neutrality has elevated interest in green hydrogen production,which does not rely on fossil fuels.Among various hydrogen production technologies,anion exchange membrane water electrolyzer(AEMWE)has emerged as a next-generation technology known for its high hydrogen production efficiency and its ability to use non-metal catalysts.However,this technology faces significant challenges,particularly in terms of the membrane durability and low ionic conductivity.To address these challenges,research efforts have focused on developing membranes with a new backbone structure and anion exchange groups to enhance durability and ionic conductivity.Notably,the super-acid-catalyzed condensation(SACC)synthesis method stands out due to its user convenience,the ability to create high molecular weight(MW)polymers,and the use of oxygen-tolerant organic catalysts.Although the synthesis of anion exchange membranes(AEMs)using the SACC method began in 2015,and despite growing interest in this synthesis approach,there remains a scarcity of review papers focusing on AEMs synthesized using the SACC method.The review covers the basics of SACC synthesis,presents various polymers synthesized using this method,and summarizes the development of these polymers,particularly their building blocks including aryl,ketone,and anion exchange groups.We systematically describe the effects of changes in the molecular structure of each polymer component,conducted by various research groups,on the mechanical properties,conductivity,and operational stability of the membrane.This review will provide insights into the development of AEMs with superior performance and operational stability suitable for water electrolysis applications.展开更多
Crystalline perovskite oxides are regarded as promising electrocatalysts for water electrolysis,particularly for anodic oxygen evolution reactions,owing to their low cost and high intrinsic activity.Perovskite oxides ...Crystalline perovskite oxides are regarded as promising electrocatalysts for water electrolysis,particularly for anodic oxygen evolution reactions,owing to their low cost and high intrinsic activity.Perovskite oxides with noncrystalline or amorphous characteristics also exhibit promising electrocatalytic performance toward electrochemical water splitting.In this review,a fundamental understanding of the characteristics and advantages of crystalline,noncrystalline,and amorphous perovskite oxides is presented.Subsequently,recent progress in the development of advanced electrocatalysts for water electrolysis by engineering and breaking the crystallinity of perovskite oxides is reviewed,with a special focus on the underlying structure–activity relationships.Finally,the remaining challenges and unsolved issues are presented,and an outlook is briefly proposed for the future exploration of next-generation water-splitting electrocatalysts based on perovskite oxides.展开更多
The determination of bubble size distribution is a prerequisite for the study of gas-liquid two-phase flow characteristics in electrolytic cells.Here the departure diameter of hydrogen bubbles and oxygen bubbles and t...The determination of bubble size distribution is a prerequisite for the study of gas-liquid two-phase flow characteristics in electrolytic cells.Here the departure diameter of hydrogen bubbles and oxygen bubbles and their detachment process from a nickel wire electrode during water electrolysis are studied using high-speed photography.The results show that in industrial alkaline environment,the departure diameters of most hydrogen bubbles and oxygen bubbles are generally smaller than 60μm and 250μm with the current density ranges from 0.15 to 0.35A/cm^(2).The adhesion force of hydrogen bubbles on a nickel wire is found to be so weak that they can separate with a tiny size.The diameters of oxygen bubbles conform to normal distribution,and its distribution range widens with the increase of current density.The theoretical analysis show that the comprehensive conversion rate of current-to-bubble is unexpectedly low especially at low current densities,which may be attributed to the loss of gas components caused by bubble detachment mode.The majority of oxygen bubbles detach by a sudden bounce after coalescence,which may bring strong disturbance to the concentration boundary layer.This also indicates the coalescence-induced bubble departure mode may occupy a dominant position in the electrolyzers.展开更多
The metal-lightweighted electrocatalysts for water splitting are highly desired for sustainable and economic hydrogen energy deployments,but challengeable.In this work,a low-content Ni-functionalized approach triggers...The metal-lightweighted electrocatalysts for water splitting are highly desired for sustainable and economic hydrogen energy deployments,but challengeable.In this work,a low-content Ni-functionalized approach triggers the high capability of black phosphorene(BP)with hydrogen and oxygen evolution reaction(HER/OER)bifunctionality.Through a facile in situ electro-exfoliation route,the ionized Ni sites are covalently functionalized in BP nanosheets with electron redistribution and controllable metal contents.It is found that the as-fabricated Ni-BP electrocatalysts can drive the water splitting with much enhanced HER and OER activities.In 1.0 M KOH electrolyte,the optimized 1.5 wt%Nifunctionalized BP nanosheets have readily achieved low overpotentials of 136 mV for HER and 230 mV for OER at 10 mA cm^(−2).Moreover,the covalently bonding between Ni and P has also strengthened the catalytic stability of the Ni-functionalized BP electrocatalyst,stably delivering the overall water splitting for 50 h at 20 mA cm^(−2).Theoretical calculations have revealed that Ni–P covalent binding can regulate the electronic structure and optimize the reaction energy barrier to improve the catalytic activity effectively.This work confirms that Ni-functionalized BP is a suitable candidate for electrocatalytic overall water splitting,and provides effective strategies for constructing metal-lightweighted economic electrocatalysts.展开更多
基金financially supported by the National Natural Science Foundation of China(No.22205205)the Natural Science Foundation of Zhejiang Province(No.LQ24E040002)the Science Foundation of Zhejiang Sci-Tech University(ZSTU)(Nos.21062337Y,LW-YP2024076)。
文摘Integrating electrochemical upgrading of glycerol and water electrolysis is regarded as a promising and energy-saving approach for the co-production of chemicals and hydrogen.However,developing efficient electrocatalyst towards this technology remains challenging.Herein,a metallic cobalt mediated molybdenum nitride heterostructural material has been exploited on nickel foam(Co@Mo_(2)N/NF)for the glycerol oxidation reaction(GOR)and hydrogen evolution reaction(HER).Remarkably,the obtained Co@Mo_(2)N/NF realizes eminent performance with low overpotential of 49 mV at 50 mA/cm^(2)for HER and high Faradaic efficiency of formate of 95.03%at 1.35 V vs.RHE for GOR,respectively.The systematic in-situ experiments reveal that the Co@Mo_(2)N heterostructure promotes the cleavage of C-C bond in glycerol by active CoOOH species and boosts the conversion of glycerol to aldehyde intermediates to formate product.Moreover,the density functional theory(DFT)calculations confirm the strong interaction at Co@Mo_(2)N interface,which contributes to the optimized water dissociation and the transformation of H^(*)to H^(2).Benefiting from those advantages,the built HER||GOR electrolyzer delivers a low voltage of 1.61 V at 50 mA/cm^(2),high Faradaic efficiency,and robust stability over 120 h for sustained and stable electrolysis.
基金supported by the National Key Research and Development Program of China(No.2021YFB4001305).
文摘Urgent requirements of the renewable energy boost the development of stable and clean hydrogen,which could effectively displace fossil fuels in mitigating climate changes.The efficient interconversion of hydrogen and electronic is highly based on polymer electrolyte membrane fuel cells(PEMFCs)and water electrolysis(PEMWEs).However,the high cost continues to impede large-scale commercialization of both PEMFC and PEMWE technologies,with the expense primarily attributed to noble catalysts serving as a major bottleneck.The reduction of Pt loading in PEMFCs is essential but limited by the oxygen transport resistance in the cathode catalyst layers(CCLs),while the oxygen transport in anode catalyst layers(ACLs)in PEMWEs also being focused as the Ir/IrO_(x) catalyst reduced.The pore structure and the catalyst-ionomer agglomerates play important roles in the oxygen transport process of both PEMFCs and PEMWEs due to the similarity of membrane electrode assembly(MEA).Herein,the oxygen transport mechanism of PEMFCs in pore structure and ionomer thin films in CCLs is systematically reviewed,while state-of-the-art strategies are presented for enhancing oxygen transport and performance through materials and structural design.The deeply research opens avenues for exploring similar key scientific problems in oxygen transport process of PEMWEs and their further development.
基金funding provided by the National Key R&D Program of China (Grant No. 2021YFB3801301)National Natural Science Foundation of China (Grant Nos. 22075076, 22208097 and 22378119)Shanghai Pilot Program for Basic Research (22TQ1400100-4)。
文摘Seawater electrolysis for hydrogen production faces inherent challenges, including side reactions, corrosion, and scaling, stemming from the intricate composition of seawater. In response, researchers have turned to continuous water splitting using forward osmosis(FO)-driven seawater desalination. However, the necessity of a neutral electrolyte hampers this strategy due to the limited current density and scarcity of precious metals. Herein, this study applies alkali-durable FO membranes to enable self-sustaining seawater splitting, which can selectively withdraw water molecules, from seawater, via concentration gradient. The membranes demonstrates outstanding perm-selectivity of water/ions(~5830 mol mol^(-1)) during month-long alkaline resistance tests, preventing electrolyte leaching(>97% OHàretention) while maintaining ~95%water balance(V_(FO)= V_(electrolysis)) via preserved concentration gradient for consistent forward-osmosis influx of water molecules. With the consistent electrolyte environment protected by the polyamide FO membranes, the Ni Fe-Ar-P catalyst exhibits promising performance: a sustain current density of 360 m A cmà2maintained at the cell voltage of 2.10 V and 2.15 V for 360 h in the offshore seawater, preventing Cl/Br corrosion(98% rejection) and Mg/Ca passivation(99.6% rejection). This research marks a significant advancement towards efficient and durable seawater-based hydrogen production.
基金support from the National Natural Science Foundation of China(Grant No.52006029)the Promotion Foundation for Young Science and Technology Talents in Jilin Province(Grant No.QT202113)+2 种基金the Special Foundation of Industrial Innovation in Jilin Province(Grant No.2019C056-2)the Special Foundation for Outstanding Young Talents Training in Jilin(Grant No.20200104107)the UK EPSRC(EP/W03784X/1)。
文摘Production of green hydrogen through water electrolysis powered by renewable energy sources has garnered increasing attention as an attractive strategy for the storage of clean and sustainable energy.Among various electrolysis technologies,the emerging anion exchange membrane water electrolyser(AEMWE)exhibits the most potential for green hydrogen production,offering a potentially costeffective and sustainable approach that combines the advantages of high current density and fast start from proton exchange membrane water electrolyser(PEMWE)and low-cost catalyst from traditional alkaline water electrolyser(AWE)systems.Due to its relatively recent emergence over the past decade,a series of efforts are dedicated to improving the electrochemical reaction performance to accelerate the development and commercialization of AEMWE technology.A catalytic electrode comprising a gas diffusion layer(GDL)and a catalyst layer(CL)is usually called a gas diffusion electrode(GDE)that serves as a fundamental component within AEMWE,and also plays a core role in enhancing mass transfer during the electrolysis process.Inside the GDEs,bubbles nucleate and grow within the CL and then are transported through the GDL before eventually detaching to enter the electrolyte in the flow field.The transfer processes of water,gas bubbles,charges,and ions are intricately influenced by bubbles.This phenomenon is referred to as bubble-associated mass transfer.Like water management in fuel cells,effective bubble management is crucial in electrolysers,as its failure can result in various overpotential losses,such as activation losses,ohmic losses,and mass transfer losses,ultimately degrading the AEMWE performance.Despite significant advancements in the development of new materials and techniques in AEMWE,there is an urgent need for a comprehensive discussion focused on GDEs,with a particular emphasis on bubbleassociated mass transfer phenomena.This review aims to highlight recent findings regarding mass transfer in GDEs,particularly the impacts of bubble accumulation;and presents the latest advancements in designing CLs and GDLs to mitigate bubble-related issues.It is worth noting that a series of innovative bubble-free-GDE designs for water electrolysis are also emphasized in this review.This review is expected to be a valuable reference for gaining a deeper understanding of bubble-related mass transfer,especially the complex bubble behavior associated with GDEs,and for developing innovative practical strategies to advance AEMWE for green hydrogen production.
基金supported by the collaborative research project of Hyundai Motor Company.Also,this work was supported by the National Research Foundation of Korea(NRF)grant funded by the Korea government(MSIT)(No.RS-2024-00406086,RS-2024-00338569,and RS-2024-00467191)。
文摘The commercialization of proton exchange membrane water electrolysis(PEMWE)for green hydrogen production hinges on the development of low-cost,high-performance titanium porous transport layers(PTLs).This study introduces a triple-layer Ti-PTL with a graded porous structure and a 75%ultra-high porosity backing layer,fabricated through tape casting and roll calendering.This triple-layer PTL,composed of a microporous layer,an interlayer,and a highly porous backing layer,enhances catalyst utilization,mechanical integrity,and mass transport.Digital twin technology using X-ray revealed increased contact area and triple-phase boundary at the interface with the catalyst layer,significantly improving oxygen evolution reaction kinetics.Numerical simulations demonstrated that the strategically designed porous structure of the triple-layer PTL facilitates efficient oxygen transport,mitigates oxygen accumulation,and improves reactant accessibility.Electrochemical evaluations showed improved performance,achieving 127 mV reduction in voltage at 2 A cm^(-2)compared to a commercial PTL,highlighting its potential to enhance PEMWE efficiency and cost-effectiveness.
基金supported by the National Natural Science Foundation of China(22005072,21965006)Guizhou Provincial Key Technology R&D Program(Qian Ke He support(2023)General 122)+3 种基金Guiyang Guian Science and Technology Personnel Training Project([2024]2-13)Youth Science and Technology Talent Development Project from Guizhou Provincial Department of Education(KY[2022]163)Guizhou Provincial Science and Technology Foundation(KYJZ[2024]029)the ETS Marcelle-Gauvreau Engineering Research Chair program.
文摘Atomically dispersed metal site(ADMS)materials have emerged as a promising class of materials for electrocatalysis reactions in the field of energy conversion.Characterized by individual metal atoms dispersed on suitable supports,ADMS materials provide unique catalytic sites with highly tunable electronic structures.This review summarizes recent advancements in the field,with a focus on the critical roles of support materials,coordination environments,and the mechanisms underlying catalytic activity at the atomic level.First,commonly used density functional theory(DFT)simulations are reviewed,emphasizing their pivotal role in elucidating reaction mechanisms and predicting the behavior of ADMS in electrochemical reactions for hydrogen energy utilization.Then,advancements in ADMS for half-cell electrochemical reactions,including oxygen evolution reaction,hydrogen evolution reaction,and oxygen reduction reaction,as well as their applications in fuel cells and water splitting,are summarized.Finally,the challenges and future prospects of ADMS are discussed.This review underscores the transformative potential of ADMS in electrocatalysis,paving the way for innovative and sustainable energy conversion technologies.
文摘Bifunctional Ir catalysts for proton exchange membrane(PEM)water electrolysis offer transformative potential by streamlining electrolyzer while achieving efficient performance remains challenging due to the distinct conditions required for oxygen and hydrogen evolution reaction(OER and HER).Herein,we propose a theory-directed design of Ir-based bifunctional catalysts,Ir nanoparticles supported on mesoporous carbon spheres embedded with MoSe_(2)(Ir/MoSe_(2)@MCS),leveraging a work function(WF)-induced spontaneous built-in electric field to enhance catalytic performance.They demonstrate exceptional kinetics for both OER and HER,and potential application in the practical PEM electrolyzer,showcasing the effectiveness of this innovative approach.Low overpotentials of 252 mV for OER and 28 mV for HER to drive 10 mA cm^(-2)were observed,and the PEM electrolyzer showed the current density of 2 A cm^(-2)at 1.87 V and maintained stable activity at 1.65 V for over 30 h to deliver 1 A cm^(-2).Density functional theory calculations reveal that the WF difference at Ir/MoSe_(2)interface induces a spontaneous built-in electric field with asymmetric charge distributions,that modulate the electronic environment and d-band center of Ir promoting bifunctional active phase formation.This significantly lowers reaction barriers for water splitting by balancing intermediate adsorption,endowing the bifunctional activity.
基金supported by the National Natural Science Foundation of China(Grant No.22275210)the Natural Science Foundation of Shandong Province(Grant No.ZR2024QB025,ZR2023ME155)the Taishan Scholar Project of Shandong Province(tsqn202306226)。
文摘Optimizing the energy barrier of 2H-to-1T phase transformation plays a crucial role in modulating the intrinsic electronic structure of MoS_(2)to achieve satisfactory water-splitting performance,but remains a significant challenge.Herein,we report a vacancy occupation-triggered phase transition strategy to fabricate a core-shell 1T phase nanorod structure,which is composed of S-vacancies decorated MoS_(2)as the core,and N,P co-doped carbons as the shell(1T-MoS_(2)@NPC).The co-insertion of N and P dopants into MoS_(2)can occupy partial S-vacancies,triggering a phase transformation from the semiconducting 2H phase to the conducting 1T phase with a reduced energy barrier.Profiting from the strong coupling effect between N,P dopants and S-vacancies,the as-made 1T-MoS_(2)@NPC exhibits excellent electrocatalytic activity for both HER(η_(10)=148 m V)and OER(η_(10)=232 mV)in alkaline solution.Meanwhile,a low cell voltage of 1.62 V is needed to drive a current density of 10mA cm^(-2)in 1.0 M KOH electrolyte.The theoretical calculation results reveal that the S-vacancies decorated C atoms in the meta-position relative to N,P atoms represent the most active HER and OER sites,which synergistically upshift the d band center and balance the rate-determining step,thus ensuring the simultaneous optimization of adsorption free energy and electronic structure.This vacancy-occupation-derived phase transformation strategy caused by non-metallic doping may provide valuable guidance for enhancing the performance of alkaline water electrolysis.
文摘Since the beginning of the 20th century,alkaline electrolysis has been used as a proven method for producing hydrogen on a megawatt scale.The existence of parasitic shunt currents in alkaline water electrolysis,which is utilized to produce clean hydrogen,is investigated in this work.Analysis has been done on a 20-cell stack.Steel end plates,bipolar plates,and an electrolyte concentration of 6 M potassium hydroxide are all included in the model.The Butler-Volmer kinetics equations are used to simulate the electrode surfaces.Ohmic losses are taken into consideration in both the electrode and electrolyte phases,although mass transport constraints in the gas phase are not.Using an auxiliary sweep to solve equations,the model maintains an isothermal condition at 85℃ while adjusting the average cell voltage between 1.3 and 1.8 V.The results show that lower shunt currents in the outlet channels as opposed to the intake channels are the result of the electrolyte’s lower effective conductivity in the upper channels,which is brought on by a lower volume fraction of the electrolyte.Additionally,it has been seen that the shunt currents intensify as the stack gets closer to the conclusion.Efficiency is calculated by dividing the maximum energy output(per unit of time)that a fuel cell operating under comparable conditions might produce by the electrical energy needed to generate that output inside the stack.At first,energy efficiency increases due to the rise in coulombic efficiency,peaking around 1400 mA.The subsequent decline after reaching 1400 mA is linked to an increase in stack voltage at elevated current levels.
基金supported by the National Key Research and Development Program of China(No.2021YFA1500400)the National Natural Science Foundation of China(No.22175163)+3 种基金the Natural Science Foundation of Anhui Province(No.2208085UD04)Anhui Development and Reform Commission(Nos.AHZDCYCX-LSDT2023-08 and AHZDCYCX-LSDT2023-07)the Department of Ecology and Environment of Anhui Province(No.2023hb0018)the Fundamental Research Funds for the Central Universities(No.WK2060000016).
文摘Despite the cost and activity advantages,ruthenium-based oxygen evolution reaction(OER)catalysts face severe stability problems for proton exchange membrane water electrolysis(PEM-WE)due to Ru dissolution.Although tremendous attention has been paid to enhancing the stability and activity under small current density in three electrode systems,there still lacks validation under industrial current density at the device level.Aiming at this issue,we report highly active and durable ruthenium-iridium alloyed oxides(IrRuO_(x))as the acidic OER catalyst for PEM-WE with exceptional durability for 1600 h at an industrial current density of 2.0 A·cm^(−2).X-ray absorption spectroscopy reveals that the introduction of iridium modulates the electronic structure of Ru and strengthens the local Ru–O bonds in RuO_(2),which is crucial for ensuring activity and stability.As a result,in comparison with its RuO_(2) counterpart,IrRuO_(x) works stably against the Ru leaching-induced catalytic layer breakage during the stability test.This work demonstrates the great potential of IrRuO_(x) as the practical OER catalyst for the application in PEM-WE.
基金Entrepreneurial and innovative team project of Ningbo Yinzhou District,Grant/Award Number:X.W.National Natural Science Foundation of China,Grant/Award Number:22379047Talent research start-up project of Zhejiang Wanli University,Grant/Award Number:SC1032345280480。
文摘The electrocatalytic water-splitting process is widely acknowledged as the most sustainable and environmentally friendly technology for hydrogen(H2)production.However,its energy efficiency is significantly constrained by the kinetically slow oxygen evolution reaction(OER)at the anode,which accounts for about 90%of the electrical energy consumption in the water-splitting process.A new strategy is urgently needed to reduce its energy consumption.In recent years,electrochemical oxidation of small molecules has been considered for replacement of OER for efficient H2 production,due to its benign operational conditions,low theoretical thermodynamic potential,high conversion efficiency and selectivity,and environmental sustainability.Hybrid electrolysis systems,by integrating cathodic hydrogen evolution reaction with anodic oxidation of small molecules,have been introduced,which can generate high-purity H2 and produce value-added products or pollutant degradation.In this review,we highlight the recent advancements and significant milestones achieved in hybrid water electrolysis systems.The focus is on non-noble metal electrocatalysts,reaction mechanisms,and the construction of electrolyzers.Additionally,we present the prevailing challenges and future perspectives pertinent to the evolution of this burgeoning technology.
基金supported by the National Key Research and Development Program(2022YFB4202200)the Fundamental Research Funds for the Central Universities and sponsored by Shanghai Pujiang Program(22PJ1413100)。
文摘Green hydrogen produced by water electrolysis combined with renewable energy is a promising alternative to fossil fuels due to its high energy density with zero-carbon emissions.Among water electrolysis technologies,the anion exchange membrane(AEM) water electrolysis has gained intensive attention and is considered as the next-generation emerging technology due to its potential advantages,such as the use of low-cost non-noble metal catalysts,the relatively mature stack assembly process,etc.However,the AEM water electrolyzer is still in the early development stage of the kW-level stack,which is mainly attributed to severe performance decay caused by the core component,i.e.,AEM.Here,the review comprehensively presents the recent progress of advanced AEM from the view of the performance of water electrolysis cells.Herein,fundamental principles and critical components of AEM water electrolyzers are introduced,and work conditions of AEM water electrolyzers and AEM performance improvement strategies are discussed.The challenges and perspectives are also analyzed.
基金supported by the Korea Institute of Energy Technology Evaluation and Planning(KETEP)grant from the Ministry of Trade,Industry&Energy,Republic of Korea(No.20213030040590)the National R&D Program through the National Research Foundation of Korea(NRF)funded by the Ministry of Science and ICT(NRF-2021K1A4A8A01079455)。
文摘Continuous efforts are underway to reduce carbon emissions worldwide in response to global climate change.Water electrolysis technology,in conjunction with renewable energy,is considered the most feasible hydrogen production technology based on the viable possibility of large-scale hydrogen production and the zero-carbon-emission nature of the process.However,for hydrogen produced via water electrolysis systems to be utilized in various fields in practice,the unit cost of hydrogen production must be reduced to$1/kg H_(2).To achieve this unit cost,technical targets for water electrolysis have been suggested regarding components in the system.In this paper,the types of water electrolysis systems and the limitations of water electrolysis system components are explained.We suggest guideline with recent trend for achieving this technical target and insights for the potential utilization of water electrolysis technology.
基金supported by the National Key Research and Development Program(No.2022YFB4202200)the Fundamental Research Funds for the Central Universities.
文摘Green hydrogen(H_(2))produced by renewable energy powered alkaline water electrolysis is a promising alternative to fossil fuels due to its high energy density with zero-carbon emissions.However,efficient and economic H_(2) production by alkaline water electrolysis is hindered by the sluggish hydrogen evolution reaction(HER)and oxygen evolution reaction(OER).Therefore,it is imperative to design and fabricate high-active and low-cost non-precious metal catalysts to improve the HER and OER performance,which affects the energy efficiency of alkaline water electrolysis.Ni_(3)S_(2) with the heazlewoodite structure is a potential electrocatalyst with near-metal conductivity due to the Ni–Ni metal network.Here,the review comprehensively presents the recent progress of Ni_(3)S_(2)-based electrocatalysts for alkaline water electrocatalysis.Herein,the HER and OER mechanisms,performance evaluation criteria,preparation methods,and strategies for performance improvement of Ni_(3)S_(2)-based electrocatalysts are discussed.The challenges and perspectives are also analyzed.
基金financially supported by the Natural Science Foundation of Hebei Province(No.B2021208030)College Students Innovation Training Program(Nos.202206224 and S2021113409001)。
文摘Hydrogen is considered as the promising energy carrier to substitute traditional fossil fuel,due to its cleanliness,renewability and high energy density.Water electrolysis is a simple and eonvenient technology for hydrogen production.The efficiency of water electrolysis for hydrogen production is limited by the electrocatalytic performances on hydrogen evolution reaction(HER)and oxygen evolution reaction(OER).The exorbitant Pt-and Ir-/Ru-based electrocatalysts as optimal HER and OER electrocatalysts,respectively,restrict water electrolysis development.Recently,non-precious metal-based high-entropy electrocatalysts have exhibited excellent electrocatalytic activities and long-term stabilities for water electrolysis,as promising precious cataly st candidates.Therefore,the construction of the high-entropy electroc atalysts is vital to water electrolysis industry.Electrodeposition technology is an efficient method for the preparation of high-entropy electrocatalysts due to its simple,fast,energy-saving and environmental-friendly advantages.Multi-component co-precipitation facilely occurs during the electroredox in electrodeposition processes.High-entropy alloys,oxides,(oxy)hydroxides,phosphides and phosphorus sulfide oxides have been successfully prepared by galvanostatic,potentiostatic electrodeposition,cyclic voltammetry,pulse,nanodroplet-mediated and cathodic plasma electrodeposition techniques.Hence,introduction of the development of high-entropy electrocatalysts synthesized by electrodeposition technology is significant to researchers and industries.Challenges and outlooks are also concluded to boost the industrial application of electrodeposition in water electrolysis and other energy conversion areas.
基金financially supported by the National Natural Science Foundation of China(21972068,22072067,22232004)the High-level Talents Project of Jinling Institute of Technology(jit-b-202164)。
文摘Precisely refining the electronic structure of electrocatalysts represents a powerful approach to further optimize the electrocatalytic performance.Herein,we demonstrate an ingenious d-d orbital hybridization concept to construct Mo-doped Co_(9)S_(8) nanorod arrays aligned on carbon cloth(CC)substrate(abbreviated as Mo-Co_(9)S_(8)@CC hereafter)as a high-efficiency bifunctional electrocatalyst toward water electrolysis.It has experimentally and theoretically validated that the 4d-3d orbital coupling between Mo dopant and Co site can effectively optimize the H_(2)O activation energy and lower H^(*)adsorption energy barrier,thereby leading to enhanced hydrogen evolution reaction(HER)and oxygen evolution reaction(OER)activities.Thanks to the unique electronic and geometrical advantages,the optimized Mo-Co_(9)S_(8)@CC with appropriate Mo content exhibits outstanding bifunctional performance in alkaline solution,with the overpotentials of 75 and 234 mV for the delivery of a current density of 10 mA cm^(-2),small Tafel slopes of 53.8 and 39.9 mV dec~(-1)and long-term stabilities for at least 32 and 30 h for HER and OER,respectively.More impressively,a water splitting electrolylzer assembled by the self-supported Mo-Co_(9)S_(8)@CC electrode requires a low cell voltage of 1.53 V at 10 mA cm^(-2)and shows excellent stability and splendid reversibility,demonstrating a huge potential for affordable and scalable electrochemical H_(2) production.The innovational orbital hybridization strategy for electronic regulation herein provides an inspirable avenue for developing progressive electrocatalysts toward new energy systems.
基金supported by the KRISS(Korea Research Institute of Standards and Science)MPI Lab.program。
文摘The increasing demand for hydrogen energy to address environmental issues and achieve carbon neutrality has elevated interest in green hydrogen production,which does not rely on fossil fuels.Among various hydrogen production technologies,anion exchange membrane water electrolyzer(AEMWE)has emerged as a next-generation technology known for its high hydrogen production efficiency and its ability to use non-metal catalysts.However,this technology faces significant challenges,particularly in terms of the membrane durability and low ionic conductivity.To address these challenges,research efforts have focused on developing membranes with a new backbone structure and anion exchange groups to enhance durability and ionic conductivity.Notably,the super-acid-catalyzed condensation(SACC)synthesis method stands out due to its user convenience,the ability to create high molecular weight(MW)polymers,and the use of oxygen-tolerant organic catalysts.Although the synthesis of anion exchange membranes(AEMs)using the SACC method began in 2015,and despite growing interest in this synthesis approach,there remains a scarcity of review papers focusing on AEMs synthesized using the SACC method.The review covers the basics of SACC synthesis,presents various polymers synthesized using this method,and summarizes the development of these polymers,particularly their building blocks including aryl,ketone,and anion exchange groups.We systematically describe the effects of changes in the molecular structure of each polymer component,conducted by various research groups,on the mechanical properties,conductivity,and operational stability of the membrane.This review will provide insights into the development of AEMs with superior performance and operational stability suitable for water electrolysis applications.
基金Program for Jiangsu Specially-AppointedProfessors。
文摘Crystalline perovskite oxides are regarded as promising electrocatalysts for water electrolysis,particularly for anodic oxygen evolution reactions,owing to their low cost and high intrinsic activity.Perovskite oxides with noncrystalline or amorphous characteristics also exhibit promising electrocatalytic performance toward electrochemical water splitting.In this review,a fundamental understanding of the characteristics and advantages of crystalline,noncrystalline,and amorphous perovskite oxides is presented.Subsequently,recent progress in the development of advanced electrocatalysts for water electrolysis by engineering and breaking the crystallinity of perovskite oxides is reviewed,with a special focus on the underlying structure–activity relationships.Finally,the remaining challenges and unsolved issues are presented,and an outlook is briefly proposed for the future exploration of next-generation water-splitting electrocatalysts based on perovskite oxides.
基金support by the National Key R&D Program of China(2022YFB4202201)Ordos-Tsinghua Innovative&Collaborative Research Program in Carbon Neutrality,Science and Technology Department of Jiangsu Province under Grand BE2022040Support Plan for Young Excellent Talents of the Department of Energy and Power Engineering,Tsinghua University.
文摘The determination of bubble size distribution is a prerequisite for the study of gas-liquid two-phase flow characteristics in electrolytic cells.Here the departure diameter of hydrogen bubbles and oxygen bubbles and their detachment process from a nickel wire electrode during water electrolysis are studied using high-speed photography.The results show that in industrial alkaline environment,the departure diameters of most hydrogen bubbles and oxygen bubbles are generally smaller than 60μm and 250μm with the current density ranges from 0.15 to 0.35A/cm^(2).The adhesion force of hydrogen bubbles on a nickel wire is found to be so weak that they can separate with a tiny size.The diameters of oxygen bubbles conform to normal distribution,and its distribution range widens with the increase of current density.The theoretical analysis show that the comprehensive conversion rate of current-to-bubble is unexpectedly low especially at low current densities,which may be attributed to the loss of gas components caused by bubble detachment mode.The majority of oxygen bubbles detach by a sudden bounce after coalescence,which may bring strong disturbance to the concentration boundary layer.This also indicates the coalescence-induced bubble departure mode may occupy a dominant position in the electrolyzers.
基金This work was jointly supported by the National Natural Science Foundation of China(Grant Nos.52371236 and 21872109)Natural Science Foundation of Shaanxi Province(No.2020JQ-165)China Postdoctoral Science Foundation(No.2019M663698).
文摘The metal-lightweighted electrocatalysts for water splitting are highly desired for sustainable and economic hydrogen energy deployments,but challengeable.In this work,a low-content Ni-functionalized approach triggers the high capability of black phosphorene(BP)with hydrogen and oxygen evolution reaction(HER/OER)bifunctionality.Through a facile in situ electro-exfoliation route,the ionized Ni sites are covalently functionalized in BP nanosheets with electron redistribution and controllable metal contents.It is found that the as-fabricated Ni-BP electrocatalysts can drive the water splitting with much enhanced HER and OER activities.In 1.0 M KOH electrolyte,the optimized 1.5 wt%Nifunctionalized BP nanosheets have readily achieved low overpotentials of 136 mV for HER and 230 mV for OER at 10 mA cm^(−2).Moreover,the covalently bonding between Ni and P has also strengthened the catalytic stability of the Ni-functionalized BP electrocatalyst,stably delivering the overall water splitting for 50 h at 20 mA cm^(−2).Theoretical calculations have revealed that Ni–P covalent binding can regulate the electronic structure and optimize the reaction energy barrier to improve the catalytic activity effectively.This work confirms that Ni-functionalized BP is a suitable candidate for electrocatalytic overall water splitting,and provides effective strategies for constructing metal-lightweighted economic electrocatalysts.
