Hydrogen production through water splitting using transition metal-based phosphide electrocatalysts represents a highly promising and sustainable energy conversion strategy.In this study,phosphating and vacancy engine...Hydrogen production through water splitting using transition metal-based phosphide electrocatalysts represents a highly promising and sustainable energy conversion strategy.In this study,phosphating and vacancy engineering are achieved via a single-step Ar plasma-assisted process.CoFePv with phosphorus vacancies(Pv)as a bifunctional electrocatalyst effectively promotes both the oxygen evolution reaction(OER)and the hydrogen evolution reaction(HER),thereby significantly facilitating overall water splitting(OWS)in alkaline media.In the OER and HER processes,the driving overpotentials needed to attain a current density of 1 A cm^(−2) are only 382 and 367 mV,respectively.Furthermore,the CoFePv(+,−)OWS electrolyzer is capable of maintaining a current density of 2 A cm^(−2) at 1.98 V under simulated industrial settings(6 M KOH and 80℃).It also demonstrates stable performance at a current density of 0.5 A cm^(−2) for a duration of 100 hours.In situ Raman spectroscopy observations show that Pv induce rapid catalyst phase reconstruction,thereby significantly enhancing the OER performance of CoFePv.Density functional theory(DFT)calculations demonstrate that phosphorus vacancies can modulate the electronic configuration of Co-Fe-P,facilitate electron transfer,and optimize the adsorption and desorption of reaction intermediates.展开更多
Engineering a phosphide-based multifunctional heterostructure with high redox activity,stability,and efficient charge kinetics for both supercapacitors and water splitting remains challenging due to sluggish reaction ...Engineering a phosphide-based multifunctional heterostructure with high redox activity,stability,and efficient charge kinetics for both supercapacitors and water splitting remains challenging due to sluggish reaction kinetics and structural instability.This study overcomes these challenges by implementing a rapid,energy-efficient approach to develop a MOF-modulated MnP@Cu_(3)P heterostructure via a hydrothermal process followed by high-temperature phosphorization.The heterostructure demonstrates superior redox activity with enhanced stability and improved charge kinetics achieving a high specific capacity of 1131 C g^(-1)as supported by density functional theory findings of increased DOS near the Fermi level.The flexible supercapacitor achieves a peak energy density of 99.20 Wh kg^(-1)and power density of 15.40 kW kg^(-1).Simultaneously,it shows exceptional hydrogen evolution reaction performance with an overpotential of η_(10)=44 mV and η_(1000)=225 mV,attributed to electron transfer from Cu to Mn via P bridging,which shifts the active centers from Mn and Cu sites to the P site,confirmed by lowestΔG_(H)^(*)value of-0.16 eV.The overall water-splitting in full-cell electrocatalyzer delivers cell voltage of E_(20)=1.48 V and E_(1000)=1.88 V and setting a new standard in solar-to-hydrogen efficiency of 20.02%.The electrolyzer cell maintained prolonged stability at industrial-scale current densities of 1.0 A cm^(-2)under alkaline electrolysis achieving an estimated hydrogen production cost of INR 146.7 or US$1.67per kilogram aligning with the cost target of $2/kg by 2026 established by the Clean Hydrogen Electrolysis Program,U.S.department of energy.Furthermore,real-phase demonstration highlights the uninterrupted hydrogen production till 6-minutes via connecting this electrocatalyzer with photovoltaic-charged supercapacitors effectively addressing solar intermittency and gas fluctuations challenges in water-electrolysis.展开更多
In order to determine the design tide levels in the areas without measured tide level data, especially in the areas where it is difficult to measure tidal levels, a calculation method based on a numerical model of tid...In order to determine the design tide levels in the areas without measured tide level data, especially in the areas where it is difficult to measure tidal levels, a calculation method based on a numerical model of tidal current is proposed. The essentials of the method are described, and its application is illustrated with an example. The results of the application show that the design tide levels calculated by the method are close to those determined by long-time measured tide level data, and its calculation precision is high, so it is feasible to use the method to determine the design tide levels in the areas.展开更多
The State Council decided to raise the retail electricity price by 0.25 Yuan/kWh from July, 2008. This will, to some extent, relieve the conflicts between power supply and demand, and decrease the economic losses in
针对断路器机械特性异常诊断中的多源信号采集与分析问题,设计出一套分合闸线圈电流和触头行程信号的采集系统,并提出了相应的异常模拟方案。通过引入分段滤波和循环差分判别进行特征提取,机器学习算法采用CatBoost模型进行单源信号的...针对断路器机械特性异常诊断中的多源信号采集与分析问题,设计出一套分合闸线圈电流和触头行程信号的采集系统,并提出了相应的异常模拟方案。通过引入分段滤波和循环差分判别进行特征提取,机器学习算法采用CatBoost模型进行单源信号的异常诊断,结合遗传算法(genetic algorithm,GA)进行参数优化,实现了基于线圈电流和触头行程的高准确率诊断。同时,利用线性判别分析(linear discriminant analysis,LDA)方法进行特征融合,提升了异常诊断效果。此外,对多种融合方法的诊断结果进行对比分析。结果表明,LDA-GA-CatBoost的特征级融合方法与基于改进的D-S证据理论(dempster-shafer theory of evidence,DST)的决策级融合方法的异常诊断率最高,均为95.82%,但LDA-GA-CatBoost的模型训练时间仅为改进的D-S证据理论的一半,更具有应用优势。展开更多
基金financially supported by the Key Research and Development Program of Shaanxi(Program No.2023-JC-YB-404 and 2024JC-ZDXM-32)。
文摘Hydrogen production through water splitting using transition metal-based phosphide electrocatalysts represents a highly promising and sustainable energy conversion strategy.In this study,phosphating and vacancy engineering are achieved via a single-step Ar plasma-assisted process.CoFePv with phosphorus vacancies(Pv)as a bifunctional electrocatalyst effectively promotes both the oxygen evolution reaction(OER)and the hydrogen evolution reaction(HER),thereby significantly facilitating overall water splitting(OWS)in alkaline media.In the OER and HER processes,the driving overpotentials needed to attain a current density of 1 A cm^(−2) are only 382 and 367 mV,respectively.Furthermore,the CoFePv(+,−)OWS electrolyzer is capable of maintaining a current density of 2 A cm^(−2) at 1.98 V under simulated industrial settings(6 M KOH and 80℃).It also demonstrates stable performance at a current density of 0.5 A cm^(−2) for a duration of 100 hours.In situ Raman spectroscopy observations show that Pv induce rapid catalyst phase reconstruction,thereby significantly enhancing the OER performance of CoFePv.Density functional theory(DFT)calculations demonstrate that phosphorus vacancies can modulate the electronic configuration of Co-Fe-P,facilitate electron transfer,and optimize the adsorption and desorption of reaction intermediates.
基金supported financially by the Ministry of Textiles(Grant No-2/3/2021-NTTM(Pt.)),Govt.of India。
文摘Engineering a phosphide-based multifunctional heterostructure with high redox activity,stability,and efficient charge kinetics for both supercapacitors and water splitting remains challenging due to sluggish reaction kinetics and structural instability.This study overcomes these challenges by implementing a rapid,energy-efficient approach to develop a MOF-modulated MnP@Cu_(3)P heterostructure via a hydrothermal process followed by high-temperature phosphorization.The heterostructure demonstrates superior redox activity with enhanced stability and improved charge kinetics achieving a high specific capacity of 1131 C g^(-1)as supported by density functional theory findings of increased DOS near the Fermi level.The flexible supercapacitor achieves a peak energy density of 99.20 Wh kg^(-1)and power density of 15.40 kW kg^(-1).Simultaneously,it shows exceptional hydrogen evolution reaction performance with an overpotential of η_(10)=44 mV and η_(1000)=225 mV,attributed to electron transfer from Cu to Mn via P bridging,which shifts the active centers from Mn and Cu sites to the P site,confirmed by lowestΔG_(H)^(*)value of-0.16 eV.The overall water-splitting in full-cell electrocatalyzer delivers cell voltage of E_(20)=1.48 V and E_(1000)=1.88 V and setting a new standard in solar-to-hydrogen efficiency of 20.02%.The electrolyzer cell maintained prolonged stability at industrial-scale current densities of 1.0 A cm^(-2)under alkaline electrolysis achieving an estimated hydrogen production cost of INR 146.7 or US$1.67per kilogram aligning with the cost target of $2/kg by 2026 established by the Clean Hydrogen Electrolysis Program,U.S.department of energy.Furthermore,real-phase demonstration highlights the uninterrupted hydrogen production till 6-minutes via connecting this electrocatalyzer with photovoltaic-charged supercapacitors effectively addressing solar intermittency and gas fluctuations challenges in water-electrolysis.
基金The National Key Fundamental Research and Development Program ("973" Program) of China under contract No. 2010CB429001
文摘In order to determine the design tide levels in the areas without measured tide level data, especially in the areas where it is difficult to measure tidal levels, a calculation method based on a numerical model of tidal current is proposed. The essentials of the method are described, and its application is illustrated with an example. The results of the application show that the design tide levels calculated by the method are close to those determined by long-time measured tide level data, and its calculation precision is high, so it is feasible to use the method to determine the design tide levels in the areas.
文摘The State Council decided to raise the retail electricity price by 0.25 Yuan/kWh from July, 2008. This will, to some extent, relieve the conflicts between power supply and demand, and decrease the economic losses in
文摘针对断路器机械特性异常诊断中的多源信号采集与分析问题,设计出一套分合闸线圈电流和触头行程信号的采集系统,并提出了相应的异常模拟方案。通过引入分段滤波和循环差分判别进行特征提取,机器学习算法采用CatBoost模型进行单源信号的异常诊断,结合遗传算法(genetic algorithm,GA)进行参数优化,实现了基于线圈电流和触头行程的高准确率诊断。同时,利用线性判别分析(linear discriminant analysis,LDA)方法进行特征融合,提升了异常诊断效果。此外,对多种融合方法的诊断结果进行对比分析。结果表明,LDA-GA-CatBoost的特征级融合方法与基于改进的D-S证据理论(dempster-shafer theory of evidence,DST)的决策级融合方法的异常诊断率最高,均为95.82%,但LDA-GA-CatBoost的模型训练时间仅为改进的D-S证据理论的一半,更具有应用优势。
