The components of proton exchange membrane water electrolysers frequently experience corrosion issues, especially at high anodic polarization, that restrict the use of more affordable alternatives to titanium. Here, w...The components of proton exchange membrane water electrolysers frequently experience corrosion issues, especially at high anodic polarization, that restrict the use of more affordable alternatives to titanium. Here, we investigate localized corrosion processes of bare and Ti-coated AISI 446 ferritic stainless steel under anodic polarization by scanning electrochemical microscopy (SECM) in sodium sulphate and potassium chloride solutions. SECM approach curves and area scans measured at open-circuit potential (OCP) of the samples in the feedback mode using a redox mediator evidence a negative feedback effect caused by the surface passive film. For the anodic polarization of the sample, the substrate generation-tip collection mode enables to observe local generation of iron (II) ions, as well as formation of molecular oxygen. For the uncoated AISI 446 sample, localized corrosion is detected in sodium sulphate solution simultaneously with oxygen formation at anodic potentials of 1.0 V vs. Ag/AgCl, whereas significant pitting corrosion is observed even at 0.2 V vs. Ag/AgCl in potassium chloride solution. The Ti-coated AISI 446 sample reveals enhanced corrosion resistance in both test solutions, without any evidence of iron (II) ions generation at anodic potentials of 1.2 V vs. Ag/AgCl, where only oxygen formation is observed.展开更多
Proton exchange membrane water electrolysis(PEMWE)is one of the most promising strategies to pro-duce green hydrogen energy,and it is crucial to exploit highly conductive and good corrosion-resistant coatings on bipol...Proton exchange membrane water electrolysis(PEMWE)is one of the most promising strategies to pro-duce green hydrogen energy,and it is crucial to exploit highly conductive and good corrosion-resistant coatings on bipolar plates(BPs),one of the core components in PEMWE cells.In this work,NbN coatings are deposited on Ti BPs by magnetron sputtering to improve the corrosion resistance and conductivity,for which the critical process parameters,such as the working pressure,partial nitrogen pressure and de-position temperature are well optimized.It is found that the compact microstructure,highly conductive δ-NbN and uniform nanoparticles play a dominant role in the synergistic improvement of the corrosion resistance and electrical conductivity of NbN coatings.The optimized NbN coatings exhibit excellent cor-rosion resistance with the low corrosion current density of 1.1×10^(-8) A cm^(-2),a high potential value of-0.005 V vs.SCE and a low ICR value of 15.8 mΩcm2@1.5 MPa.Accordingly,NbN coatings can be a promising candidate for the development of the low-cost and high-anti-corrosion Ti BPs of PEMWE.展开更多
IrO2 and IrRuOx(Ir:Ru 60:40 at%),supported by 50 wt%onto titania nanotubes(TNTs)and(3 at%Nb)Nb-doped titania nanotubes(Nb-TNTs),as electrocatalysts for the oxygen evolution reaction(OER),were synthesized and character...IrO2 and IrRuOx(Ir:Ru 60:40 at%),supported by 50 wt%onto titania nanotubes(TNTs)and(3 at%Nb)Nb-doped titania nanotubes(Nb-TNTs),as electrocatalysts for the oxygen evolution reaction(OER),were synthesized and characterized by means of structural,surface analytical and electrochemical techniques.Nb doping of titania significantly increased the surface area of the support from 145(TNTs)to 260 m2g-1(Nb-TNTs),which was significantly higher than those of the Nb-doped titania supports previously reported in the literature.The surface analytical techniques showed good dispersion of the catalysts onto the supports.The X-ray photoelectron spectroscopy analyses showed that Nb was mainly in the form of Nb(IV)species,the suitable form to behave as a donor introducing free electrons to the conduction band of titania.The redox transitions of the cyclic voltammograms,in agreement with the XPS results,were found to be reversible.Despite the supported materials presented bigger crystallite sizes than the unsupported ones,the total number of active sites of the former was also higher due to their better catalyst dispersion.Considering the outer and the total charges of the cyclic voltammograms in the range 0.1–1.4 V,stability and electrode potentials at given current densities,the preferred catalyst was Ir O2 supported on the Nb-TNTs.The electrode potentials corresponding to given current densities were between the smallest ones given in the literature despite the small oxide loading used in this work and its Nb doping,thus making the Nb-TNTs-supported IrO2 catalyst a promising candidate for the OER.The good dispersion of IrO2,high specific surface area of the Nb-doped supports,accessibility of the electroactive centers,increased stability due to Nb doping and electron donor properties of the Nb(IV)oxide species were considered the main reasons for its good performance.展开更多
The growing global energy demand and environmental concerns like greenhouse gas emissions call for clean energy solutions.Hydrogen energy,with high caloric value and low environmental impact,is a promising alternative...The growing global energy demand and environmental concerns like greenhouse gas emissions call for clean energy solutions.Hydrogen energy,with high caloric value and low environmental impact,is a promising alternative,especially when produced via proton exchange membrane water electrolysis(PEMWE).This process relies on the hydrogen evolution reaction(HER)and oxygen evolution reaction(OER),both requiring efficient electrocatalysts.Platinum(Pt),the most effectiveHER catalyst,is limited by high cost and scarcity,prompting research into Pt alternatives like ruthenium-based,transition metal derivatives,and metal-free catalysts that balance cost,efficiency,and stability.This review explores HER mechanisms,Pt-free catalyst innovations,and the impact of structural and interfacial electrode optimization on performance of HER in acidic media.It also examines electrochemical evaluation techniques,material characterization,and the role ofmachine learning in catalyst design.By providing a framework for Pt-free HER catalyst development,this review supports advancements in efficient and sustainable hydrogen energy technologies.展开更多
Proton exchange membrane water electrolysis(PEMWE)is a key technology for sustainable hydrogen production;however,its efficiency is limited by the sluggish kinetics and high overpotential of the anodic oxygen evolutio...Proton exchange membrane water electrolysis(PEMWE)is a key technology for sustainable hydrogen production;however,its efficiency is limited by the sluggish kinetics and high overpotential of the anodic oxygen evolution reaction(OER).Although RuO_(2)offers a cost-effective alternative to scarce IrO_(2)-based catalysts,its application is impeded by a fundamental trade-off between activity and stability under acidic conditions.Herein,we incorporate Hafnium(Hf)into the RuO_(2)lattice to modulate the Ru oxidation state and oxygen vacancy concentration.The introduction of Hf suppresses Ru overoxidation,while controlled generation of oxygen vacancies minimizes lattice oxygen participation.The optimized Hf_(0.1)Ru_(0.9)O_(2)catalyst exhibits a low overpotential of 187 mV at 10 mA·cm^(−2)and outstanding durability,maintaining performance for 1500 h in 0.5 M H_(2)SO_(4).Notably,a practical PEMWE device employing this catalyst achieves stable operation for over 600 h at 500 mA·cm^(−2).A combination of in-situ differential electrochemical mass spectrometry(DEMS)and operando attenuated total reflectance surface-enhanced infrared absorption spectroscopy(ATR-SEIRAS)reveal that Hf_(0.1)Ru_(0.9)O_(2)facilitates oxygen evolution primarily through a multiple-pathway mechanism dominated by the adsorbate evolution mechanism(AEM)and the oxide pathway mechanism(OPM),with effectively suppressed lattice oxygen-mediated mechanism(LOM).These findings establish a new design principle for the development of durable acidic OER electrocatalysts.展开更多
For over a decade,regenerative engineering has been defined as the convergence of advanced materials sciences,stem cell sciences,physics,developmental biology,and clinical translation for the regeneration of complex t...For over a decade,regenerative engineering has been defined as the convergence of advanced materials sciences,stem cell sciences,physics,developmental biology,and clinical translation for the regeneration of complex tissues.Recently,the field has made major strides because of new efforts made possible by the utilization of another growing field:artificial intelligence.However,there is currently no term to describe the use of artificial intelligence for regenerative engineering.Therefore,we hereby present a new term,“Regenerative Engineering AI”,which cohesively describes the interweaving of artificial intelligence into the framework of regenerative engineering rather than using it merely as a tool.As the first to define the term,regenerative engineering AI is the interdisciplinary integration of artificial intelligence and machine learning within the fundamental core of regenerative engineering to advance its principles and goals.It represents the subsequent synergetic relationship between the two that allow for multiplex solutions toward human limb regeneration in a manner different from individual fields and artificial intelligence alone.Establishing such a term creates a unique and unified space to consolidate the work of growing fields into one coherent discipline under a common goal and language,fostering interdisciplinary collaboration and promoting focused research and innovation.展开更多
Proton exchange membrane (PEM) based electrochemical systems have the capability to operate in fuel cell (PEMFC) and water electrolyser (PEMWE) modes, enabling efficient hydrogen energy utilisation and green hydrogen ...Proton exchange membrane (PEM) based electrochemical systems have the capability to operate in fuel cell (PEMFC) and water electrolyser (PEMWE) modes, enabling efficient hydrogen energy utilisation and green hydrogen production. In addition to the essential cell stacks, the system of PEMFC or PEMWE consists of four sub-systems for managing gas supply, power, thermal, and water, respectively. Due to the system's complexity, even a small fluctuation in a certain sub-system can result in an unexpected response, leading to a reduced performance and stability. To improve the system's robustness and responsiveness, considerable efforts have been dedicated to developing advanced control strategies. This paper comprehensively reviews various control strategies proposed in literature, revealing that traditional control methods are widely employed in PEMFC and PEMWE due to their simplicity, yet they suffer from limitations in accuracy. Conversely, advanced control methods offer high accuracy but are hindered by poor dynamic performance. This paper highlights the recent advancements in control strategies incorporating machine learning algorithms. Additionally, the paper provides a perspective on the future development of control strategies, suggesting that hybrid control methods should be used for future research to leverage the strength of both sides. Notably, it emphasises the role of artificial intelligence (AI) in advancing control strategies, demonstrating its significant potential in facilitating the transition from automation to autonomy.展开更多
Serious bubble clogging in flow-field channels will hinder the water supply to the electrode of proton exchange membrane water electrolyzer(PEMWE),deteriorating the cell performance.In order to address this issue,the ...Serious bubble clogging in flow-field channels will hinder the water supply to the electrode of proton exchange membrane water electrolyzer(PEMWE),deteriorating the cell performance.In order to address this issue,the dual-layer flow field design has been proposed in our previous study.In this study,the VOF(volume of fluid)method is utilized to investigate the effects of different degassing layer and base heights on the bubble behavior in channel and determine the time for the bubbles to detach from the electrode surface.However,it is very timeconsuming to get the optimal combination of base layer and degassing layer heights due to the large number of potential cases,which needs to be calculated through computation-intensive physical model.Therefore,machine learning methods are adopted to accelerate the optimization.A data-driven surrogate model based on deep neural network(DNN)is developed and successfully trained using data obtained by the physical VOF method.Based on the highly efficient surrogate,genetic algorithm(GA)is further utilized to determine the optimal heights of base layer and degassing layer.Finally,the reliability of the optimization was validated by bubble visualization in channel and electrochemical characterization in PEMWE through experiments.展开更多
Overuse of fossil fuels led to energy crises and pollution.Thus,alternative energy sources are needed.Hydrogen,with its clean and high-density traits,is seen as a future energy carrier.Producing hydrogen from electric...Overuse of fossil fuels led to energy crises and pollution.Thus,alternative energy sources are needed.Hydrogen,with its clean and high-density traits,is seen as a future energy carrier.Producing hydrogen from electricity can store renewable energy for a sustainable hydrogen economy.While much research on water electrolysis hydrogen production systems exists,comprehensive reviews of engineering applications are scarce.This review sums up progress and improvement strategies of common water electrolysis technologies(alkaline water electrolysis,proton exchange membrane water electrolysis,solid oxide water electrolysis,and anion exchange membrane water electrolysis,etc.),including component and material research and development.It also reviews these technologies by development and maturity,especially their engineering applications,discussing features and prospects.Bottlenecks of different technologies are compared and analyzed,and future directions are summarized.The aim is to link academic material research with industrial manufacturing.展开更多
基金funding from the EEA Grants 2014-2021,under Project contract No.2/2019 CoDe-PEM(EEA RO-NO-2018-0502).
文摘The components of proton exchange membrane water electrolysers frequently experience corrosion issues, especially at high anodic polarization, that restrict the use of more affordable alternatives to titanium. Here, we investigate localized corrosion processes of bare and Ti-coated AISI 446 ferritic stainless steel under anodic polarization by scanning electrochemical microscopy (SECM) in sodium sulphate and potassium chloride solutions. SECM approach curves and area scans measured at open-circuit potential (OCP) of the samples in the feedback mode using a redox mediator evidence a negative feedback effect caused by the surface passive film. For the anodic polarization of the sample, the substrate generation-tip collection mode enables to observe local generation of iron (II) ions, as well as formation of molecular oxygen. For the uncoated AISI 446 sample, localized corrosion is detected in sodium sulphate solution simultaneously with oxygen formation at anodic potentials of 1.0 V vs. Ag/AgCl, whereas significant pitting corrosion is observed even at 0.2 V vs. Ag/AgCl in potassium chloride solution. The Ti-coated AISI 446 sample reveals enhanced corrosion resistance in both test solutions, without any evidence of iron (II) ions generation at anodic potentials of 1.2 V vs. Ag/AgCl, where only oxygen formation is observed.
基金supported by the National Key Re-search and Development Program of China(No.2022YFB4002100)the National Natural Science Foundation of China(No.52271136)the Natural Science Foundation of Shaanxi Province(Nos.2019TD-020 and 2021JC-06).
文摘Proton exchange membrane water electrolysis(PEMWE)is one of the most promising strategies to pro-duce green hydrogen energy,and it is crucial to exploit highly conductive and good corrosion-resistant coatings on bipolar plates(BPs),one of the core components in PEMWE cells.In this work,NbN coatings are deposited on Ti BPs by magnetron sputtering to improve the corrosion resistance and conductivity,for which the critical process parameters,such as the working pressure,partial nitrogen pressure and de-position temperature are well optimized.It is found that the compact microstructure,highly conductive δ-NbN and uniform nanoparticles play a dominant role in the synergistic improvement of the corrosion resistance and electrical conductivity of NbN coatings.The optimized NbN coatings exhibit excellent cor-rosion resistance with the low corrosion current density of 1.1×10^(-8) A cm^(-2),a high potential value of-0.005 V vs.SCE and a low ICR value of 15.8 mΩcm2@1.5 MPa.Accordingly,NbN coatings can be a promising candidate for the development of the low-cost and high-anti-corrosion Ti BPs of PEMWE.
文摘IrO2 and IrRuOx(Ir:Ru 60:40 at%),supported by 50 wt%onto titania nanotubes(TNTs)and(3 at%Nb)Nb-doped titania nanotubes(Nb-TNTs),as electrocatalysts for the oxygen evolution reaction(OER),were synthesized and characterized by means of structural,surface analytical and electrochemical techniques.Nb doping of titania significantly increased the surface area of the support from 145(TNTs)to 260 m2g-1(Nb-TNTs),which was significantly higher than those of the Nb-doped titania supports previously reported in the literature.The surface analytical techniques showed good dispersion of the catalysts onto the supports.The X-ray photoelectron spectroscopy analyses showed that Nb was mainly in the form of Nb(IV)species,the suitable form to behave as a donor introducing free electrons to the conduction band of titania.The redox transitions of the cyclic voltammograms,in agreement with the XPS results,were found to be reversible.Despite the supported materials presented bigger crystallite sizes than the unsupported ones,the total number of active sites of the former was also higher due to their better catalyst dispersion.Considering the outer and the total charges of the cyclic voltammograms in the range 0.1–1.4 V,stability and electrode potentials at given current densities,the preferred catalyst was Ir O2 supported on the Nb-TNTs.The electrode potentials corresponding to given current densities were between the smallest ones given in the literature despite the small oxide loading used in this work and its Nb doping,thus making the Nb-TNTs-supported IrO2 catalyst a promising candidate for the OER.The good dispersion of IrO2,high specific surface area of the Nb-doped supports,accessibility of the electroactive centers,increased stability due to Nb doping and electron donor properties of the Nb(IV)oxide species were considered the main reasons for its good performance.
基金supported by the Resources Technology and Critical Minerals Trailblazer and the Commonwealth Government through the Trailblazer Universities Program as well as the Higher Degree by Research(HDR 2024)Scholarship by Curtin University,Perth,Australia.
文摘The growing global energy demand and environmental concerns like greenhouse gas emissions call for clean energy solutions.Hydrogen energy,with high caloric value and low environmental impact,is a promising alternative,especially when produced via proton exchange membrane water electrolysis(PEMWE).This process relies on the hydrogen evolution reaction(HER)and oxygen evolution reaction(OER),both requiring efficient electrocatalysts.Platinum(Pt),the most effectiveHER catalyst,is limited by high cost and scarcity,prompting research into Pt alternatives like ruthenium-based,transition metal derivatives,and metal-free catalysts that balance cost,efficiency,and stability.This review explores HER mechanisms,Pt-free catalyst innovations,and the impact of structural and interfacial electrode optimization on performance of HER in acidic media.It also examines electrochemical evaluation techniques,material characterization,and the role ofmachine learning in catalyst design.By providing a framework for Pt-free HER catalyst development,this review supports advancements in efficient and sustainable hydrogen energy technologies.
基金supported by the Fundamental Research Funds for the Central Universities(No.2024XKRC071)the National Science Fund for Young Scholars(No.22102003)The authors would like to acknowledge the AFM and EPR characterization supported by Beijing Zhongkebaice Technology Service Co.,Ltd.(www.zkbaice.cn).
文摘Proton exchange membrane water electrolysis(PEMWE)is a key technology for sustainable hydrogen production;however,its efficiency is limited by the sluggish kinetics and high overpotential of the anodic oxygen evolution reaction(OER).Although RuO_(2)offers a cost-effective alternative to scarce IrO_(2)-based catalysts,its application is impeded by a fundamental trade-off between activity and stability under acidic conditions.Herein,we incorporate Hafnium(Hf)into the RuO_(2)lattice to modulate the Ru oxidation state and oxygen vacancy concentration.The introduction of Hf suppresses Ru overoxidation,while controlled generation of oxygen vacancies minimizes lattice oxygen participation.The optimized Hf_(0.1)Ru_(0.9)O_(2)catalyst exhibits a low overpotential of 187 mV at 10 mA·cm^(−2)and outstanding durability,maintaining performance for 1500 h in 0.5 M H_(2)SO_(4).Notably,a practical PEMWE device employing this catalyst achieves stable operation for over 600 h at 500 mA·cm^(−2).A combination of in-situ differential electrochemical mass spectrometry(DEMS)and operando attenuated total reflectance surface-enhanced infrared absorption spectroscopy(ATR-SEIRAS)reveal that Hf_(0.1)Ru_(0.9)O_(2)facilitates oxygen evolution primarily through a multiple-pathway mechanism dominated by the adsorbate evolution mechanism(AEM)and the oxide pathway mechanism(OPM),with effectively suppressed lattice oxygen-mediated mechanism(LOM).These findings establish a new design principle for the development of durable acidic OER electrocatalysts.
文摘For over a decade,regenerative engineering has been defined as the convergence of advanced materials sciences,stem cell sciences,physics,developmental biology,and clinical translation for the regeneration of complex tissues.Recently,the field has made major strides because of new efforts made possible by the utilization of another growing field:artificial intelligence.However,there is currently no term to describe the use of artificial intelligence for regenerative engineering.Therefore,we hereby present a new term,“Regenerative Engineering AI”,which cohesively describes the interweaving of artificial intelligence into the framework of regenerative engineering rather than using it merely as a tool.As the first to define the term,regenerative engineering AI is the interdisciplinary integration of artificial intelligence and machine learning within the fundamental core of regenerative engineering to advance its principles and goals.It represents the subsequent synergetic relationship between the two that allow for multiplex solutions toward human limb regeneration in a manner different from individual fields and artificial intelligence alone.Establishing such a term creates a unique and unified space to consolidate the work of growing fields into one coherent discipline under a common goal and language,fostering interdisciplinary collaboration and promoting focused research and innovation.
基金support received from UK EPSRC under grant numbers EP/W018969/2,EP/V042432/1 and EP/V011863/2the Leverhulme Trust under grant number PLP-2022-001.
文摘Proton exchange membrane (PEM) based electrochemical systems have the capability to operate in fuel cell (PEMFC) and water electrolyser (PEMWE) modes, enabling efficient hydrogen energy utilisation and green hydrogen production. In addition to the essential cell stacks, the system of PEMFC or PEMWE consists of four sub-systems for managing gas supply, power, thermal, and water, respectively. Due to the system's complexity, even a small fluctuation in a certain sub-system can result in an unexpected response, leading to a reduced performance and stability. To improve the system's robustness and responsiveness, considerable efforts have been dedicated to developing advanced control strategies. This paper comprehensively reviews various control strategies proposed in literature, revealing that traditional control methods are widely employed in PEMFC and PEMWE due to their simplicity, yet they suffer from limitations in accuracy. Conversely, advanced control methods offer high accuracy but are hindered by poor dynamic performance. This paper highlights the recent advancements in control strategies incorporating machine learning algorithms. Additionally, the paper provides a perspective on the future development of control strategies, suggesting that hybrid control methods should be used for future research to leverage the strength of both sides. Notably, it emphasises the role of artificial intelligence (AI) in advancing control strategies, demonstrating its significant potential in facilitating the transition from automation to autonomy.
基金supported by a grant from National Natural Science Foundation of China(No.42302271)a grant from the Research Grants Council of the Hong Kong Special Administrative Region,China(No.N_PolyU559/21).
文摘Serious bubble clogging in flow-field channels will hinder the water supply to the electrode of proton exchange membrane water electrolyzer(PEMWE),deteriorating the cell performance.In order to address this issue,the dual-layer flow field design has been proposed in our previous study.In this study,the VOF(volume of fluid)method is utilized to investigate the effects of different degassing layer and base heights on the bubble behavior in channel and determine the time for the bubbles to detach from the electrode surface.However,it is very timeconsuming to get the optimal combination of base layer and degassing layer heights due to the large number of potential cases,which needs to be calculated through computation-intensive physical model.Therefore,machine learning methods are adopted to accelerate the optimization.A data-driven surrogate model based on deep neural network(DNN)is developed and successfully trained using data obtained by the physical VOF method.Based on the highly efficient surrogate,genetic algorithm(GA)is further utilized to determine the optimal heights of base layer and degassing layer.Finally,the reliability of the optimization was validated by bubble visualization in channel and electrochemical characterization in PEMWE through experiments.
基金the National Natural Science Foundation of China(Grant No.22478423)for the support.
文摘Overuse of fossil fuels led to energy crises and pollution.Thus,alternative energy sources are needed.Hydrogen,with its clean and high-density traits,is seen as a future energy carrier.Producing hydrogen from electricity can store renewable energy for a sustainable hydrogen economy.While much research on water electrolysis hydrogen production systems exists,comprehensive reviews of engineering applications are scarce.This review sums up progress and improvement strategies of common water electrolysis technologies(alkaline water electrolysis,proton exchange membrane water electrolysis,solid oxide water electrolysis,and anion exchange membrane water electrolysis,etc.),including component and material research and development.It also reviews these technologies by development and maturity,especially their engineering applications,discussing features and prospects.Bottlenecks of different technologies are compared and analyzed,and future directions are summarized.The aim is to link academic material research with industrial manufacturing.
