The bimetallic heterostructure Pt-Au nanoparticle array on Indium Tin Oxide electrode by electrodeposition and their high activity for the electrochemical oxidation of methanol

Abstract

The stability of Pt-based catalyst for methanol oxidation reaction (MOR) is the main hot topic to the commercial applications of direct methanol fuel cells (DMFCs) at present. In this article, a novel bimetallic heterostructure Pt-Au nanoparticles array catalyst on Indium Tin Oxide (ITO/AuNPs/PtNPs) for direct methanol fuel cells was synthesized through a facile two-step electrodeposition. Compared to ITO/PtNPs electrode, ITO/AuNPs/PtNPs delivers excellent activity and operational durability towards MOR. The turn over number (TON) of the as-prepared ITO/AuNPs/PtNPs is estimated as ~2.4 times higher than value of ITO/PtNPs at 0.06 V. The ability of resistance to CO poisoning for ITO/AuNPs/PtNPs is also evaluated, the If/Ib ratio of ITO/AuNPs/PtNPs and ITO/PtNPs is 2.0, 1.2, respectively. The enhanced properties of ITO/AuNPs/PtNPs for activity and durability can be ascribed to a high specific surface area, which could effectively promote the oxidation of methanol on Pt. Furthermore, Au can also greatly promote the transformation from CO-likes to CO2 on Pt sites. The synergetic effects provide a guarantee for highly efficient methanol oxidation for ITO/AuNPs/PtNPs.