Electrodeposition of metals in catalyst synthesis: The case of platinum monolayer electrocatalysts

Abstract

We have described the use of several metal electrodepositon techniques in syntheses of a new class of electrocatalysts comprising a PtML on metal or alloy nanoparticles. These electrocatalysts can dramatically reduce the Pt content, while affording enhanced catalytic activity. The galvanic displacement of a Cu UPD monolayer by Pt provides a uniquely convenient way of uniformly depositing a metal monolayer on carbon-supported metal nanoparticles in a surface-limited reaction controllable to a small fraction of a monolayer. This procedure can be extended into the area of thin film metal electrodeposition.19, 21-23, 47-49 Scale-up of this synthesis method is possible and successfully tested up to 50 grams per batch.43 The method facilitates growing various nanoparticles architectures with controllable thickness of components in stratified structures. The PtML electrocatalysts described above can remove the remaining obstacles in using fuel cells in automotive application. In addition, these findings indicate the broad applicability of the PtML catalysts and the possibility of extending this concept to the catalysts based on other noble metals which could prolong the availability of Pt for future use. The environmental benefits resulting from the use of fuel cells in transportation would be an especially important result of the application of PtML electrocatalysts.