Confining Platinum-Metal Alloys in Mesoporous Carbon Hollow Spheres for Enhanced Methanol Oxidation Reactions

Abstract

Active and durable electrocatalysts for the methanol oxidation reaction (MOR) are crucial for realizing the commercial applications of direct methanol fuel cell technology. However, the Pt-based catalysts extensively utilized in MOR are limited by resource scarcity and CO poisoning, a major degrader of MOR activity. Herein, PtRu bimetallic catalysts with ultrafine nanoparticles and a robust structure were synthesized by confining PtM alloys within the shells of mesoporous carbon hollow spheres (PtM@MCHS). PtRu@MCHS delivered superior electrocatalytic activity and excellent CO-poisoning tolerance towards the MOR, with a mass activity and specific activity of 5108 mA mgPt−1 and 3.3 mA cm−2. These values were 4.3 and 2.3 times higher those of Pt/C, respectively. Experimental and density functional theory calculation results revealed that Ru modulates the electronic structure of the surface Pt in PtRu@MCHS, weakening of the affinity between Pt and CO in PtRu@MCHS relative to that observed in Pt@MCHS.

Keywords: PtM alloys, Confinement effect, Mesoporous carbon hollow spheres, methanol oxidation reaction