甲酸在表面合金电催化剂上氧化的原位FTIR反射光谱研究

运用原位红外反射光谱(FTIRS)和电化学循环伏安法(CV)研究了甲酸在三种不同电极上的电催化特性．结果表明甲酸在碳栽铂电极(Pt／GC)上的电催化氧化机理与本体铂电极(I^3t)相类似，即可以通过活性中问体或毒性中间体氧化至CO2.Pt／GC对甲酸的氧化比Pt具有更高的电催化活性．Pt／GC表面以Sb吸附原子修饰的电极(Sb—Pt／GC)上，甲酸氧化的起始电位(Ei)提前至-0．10V，氧化电流峰电位(Ep)提前至0．34V，氧化峰电流(jp)值增加了7.28倍，半峰宽(FWHM)为0．30V同样，Surface alloy／GC电极上，E1为-0．12V、Ep为0．32V和jp为7．25mA／cm^2，相对Pt／GC分别负移了0.22V、0．02V和增大了8．15倍，半峰宽(FWHM)为0．5V．表明Sb—Pt／GC和Surface alloy／GC电极不仅能够有效地抑制毒性中间体CO的生成，而且还可以显著地提高其对活性中间体的氧化的电催化活性．

In Situ FTIRS Studies of HCOOH Oxidation on Surface Alloy Electrocatalysts

Electrocatalytic properties of three electrodes for formic acid oxidation are studied by using electrochemical in situ FTIR spectroscopy and cyclic voltammetry in this paper. It is demonstrated that the electrocatalytical mechanism of formic acid oxidation on platinum dispersed carbon(Pt/GC)is similar to that on massive platinum, which involves two paths, i.e. one way through active intermediate and another through poison intermediate to CO2. The Pt/GC exhibits higher catalytivity than pure platinum. The electrode of Pt/GC modified by Sb (Sb-Pt/GC)is also prepared in the work. It is observed that the onset potential (Ei) for formic acid oxidation on Sb-Pt/GC was shifted negatively for 0.20V. The peak potential (Ep) was observed to shifted negatively to 0.34V and the value of oxidation current (jp) was enhanced nearly 7.28 times. similar results were also observed on surface alloy/GC prepared. In this case, Ei and Ep was at -0.12V and 0.32V respectively, jp was enhanced about 8.15 times and FWHM (Full Width at Half Maximum) was 0.50V. It is indicated that Sb-Pt/GC and surface alloy/GC not only effectively restraint the formation of poison intermediate CO, but also significantly increase the electrocatalytic activities for oxidation of active intermediates.