一氧化碳在硫修饰铂电极上的吸附与电氧化研究(英文)  

Adsorption and Electrooxidation of Carbon Monoxide on Platinum Surfaces Modified with Sulfur

作　　者：Mathew A.Mattox Matthew W.Henney Adam Johnson 

机构地区：[1]迈阿密大学化学&生物化学系,美国俄亥俄州45056

出　　处：《电化学》2012年第6期521-536,共16页Journal of Electrochemistry

基　　金：supported by Miami University startup funds

摘　　要：吸附硫通常被认为是表面化学反应毒物,然而少量的硫能够增强铂的一氧化碳(CO)电氧化活性.本文利用常规电化学手段及表面增强拉曼光谱研究了CO在硫修饰的铂表面的电氧化.对于溶液中的CO,其在硫修饰铂电极上的起始氧化电位最多可以比非修饰电极负移超过300 mV,而且在硫覆盖度低于0.6的条件下电位负移量随覆盖度增加而增大.这一电催化活性的增强也受溶液pH值的影响.在低硫覆盖度(小于0.3)下,吸附态的CO电氧化峰值电位比非修饰铂电极负移约40 mV.然而,在高硫覆盖度下,其峰值电位比非修饰铂电极正移近30 mV.表面增强拉曼光谱显示共吸附硫使Pt—CO振动频率显著红移.作者认为这些结果是由于吸附硫弱化Pt—CO键及阻化CO在铂表面的移动引起的.Adsorbed sulfur is commonly considered as a reaction poison.However,small amounts of sulfur on platinum significantly increase the surface reactivity toward carbon monoxide（CO） electrooxidation.For the solution CO oxidation,the onset potential was shifted up to over 300 mV negative to that on S-free surface,and the extent of the negative potential shift increases with the sulfur coverage（X S） up to about 0.6.The enhanced CO oxidation also depends on the solution pH.For the adsorbed CO,at low sulfur coverages（X S 0.3）,the oxidation peak potential is about 40 mV negative to that of the corresponding clean Pt.However,at higher coverages,the peak potential is about 30 mV more positive.Surface-enhanced Raman spectra show that the adsorption of sulfur significantly redshifts the Pt—CO stretching frequency.These observations are explained by the weakening of the Pt—CO bond and the hindrance of CO diffusion by S ads.

关 键 词：电氧化 硫 一氧化碳 铂电极 表面增强拉曼光谱 

分 类 号：O646.54[理学—物理化学]