Pt(110)/Sb电极上甲酸的电催化氧化特征和动力学

研究了Sb在Pt(110)晶面上不可逆吸附电化学特性及甲酸在Sb_ad修饰Pt(110)电极Pt(110)/Sb]上的电催化氧化特征及其反应动力学.发现当扫描电位的上限E_u≤0.45V时,Sb_ad可稳定地吸附在Pt(110)表面上,从而有效地抑制了甲酸的解离吸附.与未修饰的Pt(110)上的结果相比,在Pt(110)/Sb上甲酸氧化的峰电位负移了0.35V.当θ_Sb=0.126时,Pt(110)/Sb电极对甲酸的电催化活性最高.还研究了Pt(110)/Sb上甲酸氧化反应的动力学,定量解析了不同θ_Sb下甲酸氧化的速度常数kf和传递系数β.

Kinetics and Characteristics of Electrocatalytic Oxidation of Formic Acid on Pt(110)/Sb Electrodes

The electrochemical behavior of irreversibly adsorbed antimony on Pt(110) was studied by using cyclic voltametry. The results demonstrated that the Sb_ad atoms are stable on Pt(110) when the electrode potentials are below 0.45 V( vs. SCE). We illustrated that various coverages of Sb_ad can be easily obtained by controlling the number of potential cycling and the upper limit of potential scan. It was found that the dissociative adsorption of formic acid was inhibited by the presence of Sb_ad on Pt(110) surface. The electrocatalytic effects of Sb_ad toward HCOOHelectrooxidation is demonstrated by the negative shift of oxidation potential(about 0.35 V) and the enhancement of oxidation current. The maximum current density was measured for a Sb coverage of 0.126. Based on methods developed in our previous papers, the kinetics of HCOOHelectrooxidation on Pt(110)/Sb electrodes of different θ_Sb has been studied, and both the rate constant k f and transfer coefficient β were determined quantitatively.