Understanding the hydroxyl adsorption behavior at Pt electrode surface in high-temperature alkaline solutions  

作　　者：Bo Pan Biao Liu Shaona Wang Yeqing Lv Hao Du Yi Zhang 

机构地区：[1]National Engineering Laboratory for Hydrometallurgical Cleaner Production Technology,Key Laboratory of Green Process and Engineering,Institute of Process Engineering,Chinese Academy of Sciences,Beijing 100190,China [2]University of Chinese Academy of Sciences,Beijing 100190,China

出　　处：《Chinese Journal of Chemical Engineering》2023年第2期173-179,共7页中国化学工程学报（英文版）

基　　金：the National Key Research and Development Program of China(2020YFC1909703);S&T Program of Hebei Province(21284402Z);Fangchenggang Key Research and Development(AB20014008);Lvliang Key Research and Development Program(2020GXZDYF7)。

摘　　要：Since the application in fuel cell,the electrochemical adsorption of hydroxyl has received considerable attention in recent years.While most research mainly focus on the room temperature,in this paper,the electrochemical adsorption of hydroxyl in alkaline solution at high temperature was investigated.An unusual oxidation peak was observed at-0.27 V,suggesting new behavior of hydroxyl adsorption occurred.As is known two kinds of cation hydrated clusters exist in alkaline solution,(H_(2)O)_(x-1)M^(+)-H_(2)O-O_(ad)H and(H_(2)O)_xM^(+)-O_(ad)H.For K^(+)and Cs^(+),the cluster shows unstable structure due to the weak interaction between hydrated cation and OH^(-)especially at high temperature.However,For Li^(+),Na^(+)the cluster structure would be stable,as the interaction force between the hydrated cation and OH^(-)is so strong.It was revealed that the unusual oxidation peak has some relationship with the(H_(2)O)_(x-1)M^(+)-H_(2)O-O_(ad)H cluster(K^(+)and Cs^(+))absorbed at Pt electrode surface.When the temperature was raised,(H_(2)O)_(x-1)M^(+)-H_(2)O-and-O_(ad)H was disconnected,then the O_(ad)H absorbed at Pt surface got oxidated.Based on the SEM observation,it was showed the unusual electrochemical oxidation reaction would generate platinum oxides,blocking the reactive sites at Pt electrode surface,thus reducing the electrochemical reactivity of Pt electrode.Accordingly,parameters of alkaline concentration and temperature were systematically studied,it was found that increase temperature or alkaline concentration was in favor of the unusual oxidation reaction.This study provides more understanding of hydroxyl adsorption behavior at Pt electrode surface for the high temperature water solution environment.

关 键 词：Alkaline solution Hydroxyl adsorption Cationic species High temperature Cationic hydrated clusters 

分 类 号：TM911.4[电气工程—电力电子与电力传动] O647.3[理学—物理化学]