Studies of Oxidation Processes of Methanol on Hollow CoPt Nanospheres and In situ Electrochemical Fourier Transform Infrared Spectroscopy

Abstract

Hollow CoPt nanospheres were synthesized by chemical reduction and galvanic displacement reactions. The catalyst showed good electrocatalytic activity for methanol oxidation. The results of transmission electron microscopy (TEM), energy dispersive spectromenter (EDS), and electrochemical cyclic voltammograms indicated that, in the process of electrochemical experiments carried in 0.1 mol . L-1 H2SO4 and 0.1 mol . L-1 CH3OH, hollow CoPt nanospheres were dealloying, which induced the dissolution of elemental Co from the surface of the catalyst. After the dealloying process, more Pt active sites were exposed on the surface of the catalyst and the catalyst showed better catalytic activity, as well as enhanced structural stability. The electrooxidation of methanol on the hollow CoPt nanospheres was studied on the molecular level using in situ electrochemical Fourier transform infrared (FTIR) spectroscopy. The toxic intermediate CO observed on the CoPt nanorods displayed abnormal infrared effects (AIREs). The FTIR results were similar to those obtained in an earlier experiment on the hollow CoPt nanospheres using CO as a probe molecule. All the results suggested that the dealloying method would be a useful technique for regulating the composition and performance of the catalyst. In situ electrochemical FTIR was highlighted as a potential method for studying the oxidation processes of organic molecules. It is envisaged that these methods will be widely used in the field of fuel cell research.