Unravelling Hydrogen Adsorption Kinetics on Ir(111)Electrode in Acid Solutions by Impedance Spectroscopy  

利用交流阻抗谱揭示Ir(111)电极在酸性溶液中的氢吸附动力学

作　　者：Yan-li Tang Wei Chen Mian-le Xu Zhen Wei Jun Cai Yan-xia Chen 唐延丽;陈微;许绵乐;韦臻;蔡俊;陈艳霞(中国科学技术大学化学物理系,合肥微尺度物质科学国家研究中心,合肥230026)

机构地区：[1]Hefei National Laboratory for Physical Sciences at the Microscale,Department of Chemical Physics,University of Science and Technology of China,Hefei 230026,China

出　　处：《Chinese Journal of Chemical Physics》2021年第2期179-187,I0001,共10页化学物理学报（英文）

基　　金：supported by the National Natural Science Foundation of China(No.91545124,No.21972131,No.21832004).

摘　　要：The kinetics for hydrogen(H)adsorption on Ir(111)electrode has been studied in both HClO_(4) and H_(2)SO_(4) solutions by impedance spectroscopy.In HClO_(4),the adsorption rate for H adsorption on Ir(111)increases from 1.74×10^(-8)mol·cm^(-2)·s^(-1) to 3.47×10^(-7)mol·cm^(-2)·s^(-1) with the decrease of the applied potential from 0.2 V to 0.1 V(vs.RHE),which is ca.one to two orders of magnitude slower than that on Pt(111)under otherwise identical condition.This is explained by the stronger binding of water to Ir(111),which needs a higher barrier to reorient during the under potential deposition of H from hydronium within the hydrogen bonded water network.In H_(2)SO_(4),the adsorption potential is ca.200 mV negatively shifted,accompanied by a decrease of adsorption rate by up to one order of magnitude,which is explained by the hindrance of the strongly adsorbed sulfate/bisulfate on Ir(111).Our results demonstrate that under electrochemical environment,H adsorption is strongly affected by the accompanying displacement and reorientation of water molecules that initially stay close to the electrode surface.

关 键 词：Hydrogen adsorption/desorption Electrochemical impedance spectrometry Ir(111)electrode Sulfate adsorption/desorption 

分 类 号：O647.3[理学—物理化学]