Today,Pt/C catalysts are widely used in proton exchange membrane fuel cells(PEMFCs).The practical applications of PEMFCs still face many limitations in the preparation of advanced Pt‐based catalysts,including high co...Today,Pt/C catalysts are widely used in proton exchange membrane fuel cells(PEMFCs).The practical applications of PEMFCs still face many limitations in the preparation of advanced Pt‐based catalysts,including high cost,limited life‐time,and insufficient power density.A kinetically sluggish oxygen reduction reaction(ORR)is primarily responsible for these issues.The development of advanced Pt‐based catalysts is crucial for solving these pro-blems when the large‐scale application of PEMFCs is to be realized.Herein,we demonstrate the design principle of advanced Pt‐based catalysts with an emphasis on theoretical understandings to practical applications.Generally,three main strategies(including strain effect,electronic effect,and ensemble effect)that governing the initial activity of Pt‐based electrocatalysts are ela-borated in detail in this review.Recent advanced Pt‐based ORR catalysts are summarized and we present representative achievements to further reveal the relationship of excellent ORR performance based on theoretical mechanisms.Then we focus on the preparation standards of membrane electrode assembles and testing protocols in practice.Finally,we predict the remaining challenges and present our perspectives with regards to design strategies for improving ORR performance of Pt‐based catalysts in the future.展开更多
在用高压脉冲电场(pulsed electric field,PEF)技术处理食品的过程中,脉冲电流通过电极-液体表面,引起电化学反应,导致电极腐蚀,从而影响到食品安全和设备运行。利用加速腐蚀实验研究了高压脉冲电场作用下的电极腐蚀规律,重点考察了不...在用高压脉冲电场(pulsed electric field,PEF)技术处理食品的过程中,脉冲电流通过电极-液体表面,引起电化学反应,导致电极腐蚀,从而影响到食品安全和设备运行。利用加速腐蚀实验研究了高压脉冲电场作用下的电极腐蚀规律,重点考察了不同电压幅值、脉宽和溶液电导率对电极腐蚀的影响;测试了溶液中电极材料钛离子质量浓度,以定量表征电极腐蚀程度;得到了腐蚀速度随时间的变化关系曲线。结果表明:PEF作用下电极腐蚀特性可以用传统电路模型来解释;随着电场强度由16.7 kV/cm逐步升至41.7 kV/cm、脉宽由5μs逐步升至20μs,溶液电导率由1μS/cm逐步升至600μS/cm,腐蚀会逐渐加剧,钛离子质量浓度分别由0.466μg/L至2.085μg/L、由0.4μg/L至4.855μg/L和由0.8μg/L至43.4μg/L依次上升;腐蚀由电极表面边缘倒角部分开始逐步向中心区域发展;腐蚀后电极在空气中放置氧化一段时间可使加电时腐蚀速度减慢。最后通过研究电极腐蚀规律提出了抑制或者减少腐蚀的措施。展开更多
基金NSFC,Grant/Award Numbers:21871159,21890383National Key R&D Program of China,Grant/Award Numbers:2018YFA0702003,2016YFA0202801+2 种基金National Natural Science Foundation of China,Grant/Award Numbers:21890383,21671117,21871159Science and Technology Key Project of Guangdong Province of China,Grant/Award Number:2020B010188002Beijing Municipal Science&Technology Commission,Grant/Award Number:Z191100007219003。
文摘Today,Pt/C catalysts are widely used in proton exchange membrane fuel cells(PEMFCs).The practical applications of PEMFCs still face many limitations in the preparation of advanced Pt‐based catalysts,including high cost,limited life‐time,and insufficient power density.A kinetically sluggish oxygen reduction reaction(ORR)is primarily responsible for these issues.The development of advanced Pt‐based catalysts is crucial for solving these pro-blems when the large‐scale application of PEMFCs is to be realized.Herein,we demonstrate the design principle of advanced Pt‐based catalysts with an emphasis on theoretical understandings to practical applications.Generally,three main strategies(including strain effect,electronic effect,and ensemble effect)that governing the initial activity of Pt‐based electrocatalysts are ela-borated in detail in this review.Recent advanced Pt‐based ORR catalysts are summarized and we present representative achievements to further reveal the relationship of excellent ORR performance based on theoretical mechanisms.Then we focus on the preparation standards of membrane electrode assembles and testing protocols in practice.Finally,we predict the remaining challenges and present our perspectives with regards to design strategies for improving ORR performance of Pt‐based catalysts in the future.
文摘在用高压脉冲电场(pulsed electric field,PEF)技术处理食品的过程中,脉冲电流通过电极-液体表面,引起电化学反应,导致电极腐蚀,从而影响到食品安全和设备运行。利用加速腐蚀实验研究了高压脉冲电场作用下的电极腐蚀规律,重点考察了不同电压幅值、脉宽和溶液电导率对电极腐蚀的影响;测试了溶液中电极材料钛离子质量浓度,以定量表征电极腐蚀程度;得到了腐蚀速度随时间的变化关系曲线。结果表明:PEF作用下电极腐蚀特性可以用传统电路模型来解释;随着电场强度由16.7 kV/cm逐步升至41.7 kV/cm、脉宽由5μs逐步升至20μs,溶液电导率由1μS/cm逐步升至600μS/cm,腐蚀会逐渐加剧,钛离子质量浓度分别由0.466μg/L至2.085μg/L、由0.4μg/L至4.855μg/L和由0.8μg/L至43.4μg/L依次上升;腐蚀由电极表面边缘倒角部分开始逐步向中心区域发展;腐蚀后电极在空气中放置氧化一段时间可使加电时腐蚀速度减慢。最后通过研究电极腐蚀规律提出了抑制或者减少腐蚀的措施。
