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Kinetic Implication from Temperature Effect on Hydrogen Evolution Reaction at Ag Electrode
Jing Kang,Chu-hong Lin,Yao Yao,Yan-xia Chen*
Author NameAffiliationE-mail
Jing Kang Hefei National Laboratory for Physical Sciences at Microscale, Department of Chemical Physics, Uni-versity of Science and Technology of China, Hefei 230026, China  
Chu-hong Lin Hefei National Laboratory for Physical Sciences at Microscale, Department of Chemical Physics, Uni-versity of Science and Technology of China, Hefei 230026, China  
Yao Yao Hefei National Laboratory for Physical Sciences at Microscale, Department of Chemical Physics, Uni-versity of Science and Technology of China, Hefei 230026, China  
Yan-xia Chen* Hefei National Laboratory for Physical Sciences at Microscale, Department of Chemical Physics, Uni-versity of Science and Technology of China, Hefei 230026, China yachen@ustc.edu.cn 
Abstract:
Hydrogen evolution reaction (HER) at polycrystalline silver electrode in 0.1 mol/L HClO4 solution is investigated by cyclic voltammetry in the temperature range of 278-333 K. We found that at electrode potential φa,app decreases with φ, while pre-exponential factor A remains nearly unchanged,which conforms well the prediction from Butler-Volmer equation. In contrast, with φ nega-tive shifts from the onset potential for HER to the potential of zero charge (PZC≈-0.4 V), both Ea,app and A for HER increase (e.g., Ea,app increases from 24 kJ/mol to 32 kJ/mol). The increase in Ea,app and A with negative shift in φ from -0.25 V to PZC is explained by the increases of both internal energy change and entropy change from reactants to the transition states, which is correlated with the change in the hydrogen bond network during HER. The positive entropy effects overcompensate the adverse effect from the increase in the activation energy, which leads to a net increase in HER current with the activation energy negative shift from the onset potential of HER to PZC. It is pointed out that entropy change may contribute greatly to the kinetics for electrode reaction which involves the transfer of electron and proton, such as HER.
Key words:  Hydrogen evolution reaction, Ag electrode, Temperature effect, Activation energy, Pre-exponential factor, Internal energy, Entropy change
FundProject:
从银电极上氢析出的温度效应得到的反应动力学启示
康婧,林楚红,姚瑶,陈艳霞*
摘要:
利用循环伏安法研究了多晶银电极在0.1 mol/L HClO4溶液中氢析出反应的温度效应. 发现当从析氢起始电位负向扫描至零电荷电位(-0.4 V)时,氢析出反应的表观活化能(Ea,app)和指前因子(A)均随着电势的负移而增大(对应的Ea,app从24 kJ/mol增大至32 kJ/mol).继续负向扫描至零电荷电位以后,Ea,app随电势的负移而减小但A不随电势变化. 推测Ea,app和A在零
关键词:  氢析出反应,银电极,温度效应,活化能,对称因子,内能,熵变
DOI:10.1063/1674-0068/27/01/63-68
分类号: