Mechanistic Understanding of the Effect of Surface Composition of Pt-Ru Bimetallic Alloy Electrocatalysts on HCOOH Oxidation Pathways at Acid Electrochemical Interface

摘要

abstract_textpThe effect of surface composition of Pt-Ru bimetallic alloy electrocatalysts on HCOOH oxidation mechanisms are first studied systematically at acid electrochemical interface based on DFT in this work. The present studies indicate that the growth of Pt on Ru may be not an optimal electrocatalyst. Instead, the alloying of Pt with Ru can notably enhance the direct electrooxidation activity of HCOOH. The appropriate Ru contents play an important role in determining HCOOH electrooxidation activity and Pt-Ru alloys with low Ru contents are efficient alloy catalysts. The higher Ru contents hinder CO removal and lead to CO poisonous effect on surface active sites, thereby going against HCOOH oxidation. It is also concluded that on Pt-Ru alloys the experimentally observed enhanced oxidation kinetics may be ascribed to improved direct pathways, rather than enhancement of CO tolerance. Two possible descriptors that can scale HCOOH oxidation activity are proposed based on the origin of electrocatalytic activity, which will provide theoretical guidelines for rational design of Pt-based alloy catalysts with appropriate surface composition./p/abstract_text