室温下中等浓度电解质中Pt(111)电极零电荷电势的理论模拟  

Theoretical simulations of potential of zero charge for a Pt(111) electrode immersed in electrolyte solution with medium concentrations at room temperature

作　　者：段赛[1] 田广军[1] 罗毅[2] 

机构地区：[1]瑞典皇家理工学院理论化学和生物系 [2]中国科学技术大学微尺度物质科学国家实验室,合肥230026

出　　处：《中国科学：化学》2015年第12期1304-1309,共6页SCIENTIA SINICA Chimica

基　　金：中国科学院战略性先导科技专项(XDB01020200);瑞典Goran Gustafssons自然科学和医学基金会

摘　　要：在电化学模型中,温度效应是经常被忽略的重要参量.本文采用最近发展的经典分子动力学和第一性原理杂化方法研究了室温下Pt(111)电极在0.77 mol/L NaClO_4电解质溶液中的零电荷电极电势(PZC).分子动力学结果表明,ClO_4^-弱吸附于Pt(111)表面,而Na^+则分布在整个溶液中.基于分子动力学的轨迹,第一性原理计算得到的平均PZC相对于标准氢电极为0.57 V.相较于无限稀溶液,该值正移了0.33 V.这一结果归结于ClO_4^-的弱吸附,并且趋势和实验测量值一致.计算结果同时表明,暂态PZC呈标准方差为0.60 V的准正态分布.电解质和溶剂的热运动是引起这一分布的原因.本文中的理论结果有助于深入了解双电层结构以及电催化剂的设计.The finite temperature effects on electrode potential are usually neglected in theoretical considerations.In this study,we used the recently developed hybrid classical molecular dynamics（MD） and first principles（FP）calculations to investigate the potential of zero charge（PZC） for a Pt（111） electrode immersed in a 0.77 mol/L NaClO4 electrolyte solution at room temperature.The results from MD simulations show that ClO4^- is weekly adsorbed on the Pt（111） surface,while,Na＋ distributes all over the electrolyte solution.Based on the MD trajectories,the average PZC in the electrolyte calculated by FP calculations is 0.57 V vs.potential of standard hydrogen electrode.This value shows a 0.33 V positive shift when compared with that in the dilute solutions,which could be attributed to the weak adsorption of ClO4^- and is consistent with experimental observations.Meanwhile,a quasi normal distribution of instantaneous PZC with standard deviation of 0.60 V is observed,which could be attributed to the thermal motions of the electrolyte as well as the solvent.These results at molecular level would help the understanding of structures of electric double layer and benefit the design of electrocatalysts.

关 键 词：Pt(111)电极 零电荷电势 NaClO_(4)电解质 FP//MD方法 暂态PZC 

分 类 号：O646[理学—物理化学]