Preparation of Pt-Based Bimetallic Catalysts and Electrocatalytic Performance for Methanol Oxidation

Abstract

The intermediate toxic species COads produced by electrocatalytic oxidation of methanol have a high adsorption energy on the surface of Pt active sites and are difficult to convert, which is the main reason for the poisoning and deactivation of Pt electrocatalysts in direct methanol fuel cells. In this study, a series of PtSn/CeO2-CNTs alloy catalysts were prepared by an ethylene glycol hydrothermal reduction method using CeO2-modified carbon nanotubes (CNTs) as the support. The electrochemical properties of a series of PtSn alloy catalysts were measured by using a methanol oxidation reaction (MOR) as a probe reaction. The results show that the excellent electrochemical performance is mainly attributed to the introduction of CeO2 and the synergistic effect among the Sn and Pt intermetallic nanoparticles. An in situ transient analysis platform investigated the electrocatalytic oxidation path of methanol molecules at the surface and interface of Pt100-CNTs and Pt42Sn58/CeO2-CNTs catalysts. It was clear that methanol was converted by the CO path, and the introduction of Sn and CeO2 synergistically promoted the rapid conversion of intermediate toxic species COads, which effectively improved the activity and stability of Pt catalysts and accelerated the MOR rate. It provides a new idea and basis for the rational design and optimization of Pt electrocatalysts.