氧化锰电催化析氧反应及其电极界面特性  

Oxygen evolution reaction over manganese oxides and the electrode-solution interface

作　　者：朱晓兵[1,2] 李佳佳 李怡宁[1] 杨洪月 李小松 刘景林 ZHU Xiaobing;LI Jiajia;LI Yining;YANG Hongyue;LI Xiaosong;LIU Jinglin(Center for Hydrogen Energy and Environmental Catalysis,Dalian University of Pechnology,Dalian 116024,Liaoning,China;Laboratory of Plasma Physical Chemistry,Dalian University of Technology,Dalian 116024,Liaoning,China)

机构地区：[1]大连理工大学氢能与环境催化中心,辽宁大连116024 [2]大连理工大学等离子体物理化学实验室,辽宁大连116024

出　　处：《化工学报》2021年第S01期398-405,共8页CIESC Journal

基　　金：国家自然科学基金项目(11475041)。

摘　　要：析氧半反应是速控步骤。氧化锰(MnO_(x))具有多价态,可形成多个子步骤降低活化能。二氧化钛(TiO_(2))是抗氧化性半导体。考察两种氧化锰催化剂析氧性能,即滑动弧等离子体合成MnO_(x)(pM)和商业化(cM),与商业化TiO_(2)(cT)比较。通过理想极化电极系统(IPE)解析,表达电极界面特性,揭示三相界面与活性的关联。结果表明:对两种MnO_(x)催化剂,pM比cM性能更优。碱性环境中,前者起始电位低180 mV,Tafel斜率近半。酸性中,均表现阶跃式极化,析氧性能相近。cM比cT催化剂析氧性能更优,起始电位低420 mV。溶液电阻Rs与活性变化趋势一致。对相同催化剂,考察I/C、担量、单双层结构,电容压降占比fCd与活性一致。对不同催化剂,考察cM,cT或pM,cM,fCd与活性不一致,这与多价态锰参与非法拉第过程有关。Oxygen evolution reaction(OER)is the rate-determining step for water electrolysis.Manganese oxides(MnO_(x))possess five valence states,hence with multiple steps to reduce the activation energy,and semiconductor titanium dioxide(TiO_(2))exhibits corrosion resistance.Here we demonstrate OER performance over three catalysts,of MnO_(x) synthesized by gliding arc plasma(pM)and commercial MnO_(x)(cM),and commercial TiO_(2)(cT).Of non Faradiac process,using ideal polarized electrode(IPE),it expresses the electrode-solution interface,hence reveals the association between triple phase boundary(TPB)and activity.It suggests that,the MnO_(x) of pM shows better activity than cM.In alkali,the former has 180 mV lower potential vs RHE,and nearly half Tafel slope.In acid,both the MnO_(x) catalysts show step-current polarization with similar activity.Moreover,cM shows higher activity than cT,e.g.,420 mV lower potential.The revealed solution resistance,Rs is consistent with activity.For the same catalyst,the fraction in voltage drop of capacitance fCd,is also in accordance with the activity in terms of ionomer to catalyst ratio(I/C),loading and single/double layer(s).However,for the varied catalysts,e.g.,cM versus cT,or pM versus cM,the fCd is inconsistent with the activity,which might result from involving the non-Faradiac process of MnO_(x).

关 键 词：氧化锰 二氧化钛 滑动弧等离子体 析氧反应 电极-溶液界面 

分 类 号：O646[理学—物理化学]