Electrodeposited Bimetallic (PtPd, PtRu, PtSn) Catalysts on Titanium Support for Methanol Oxidation in Direct Methanol Fuel Cells

Abstract

The electrodeposition of platinum-based catalysts (PtPd, PtRu, and PtSn) using the pulse current deposition technique was carried out on titanium substrate to prepare electrodes of different compositions to identify a possible catalyst offering high catalytic activity towards methanol oxidation (MOR). Characterization by XRD, SEM, and EDX confirmed the deposition of catalysts with the desired composition with various morphologies of dendritic, spherical, and irregular deposits for PtPd, PtRu, and PtSn, respectively. Among the various compositions and binary metals studied, electrochemical results indicate PtRu/Ti with Pt to Ru ratio of 1:1 (Pt50Ru50/Ti) to be most active with lower onset potentials for CO oxidation (0.381 V) and methanol oxidation (0.545 V) along with higher peak current density of ∼90 mA cm−2 compared to Pt/Ti (with onset potentials of 0.601 V for CO oxidation, 0.659 V for methanol oxidation and ∼68 mA cm−2 peak current density). Moreover, the MOR catalytic activity retention after 1000 accelerated durability test cycles was the highest for Pt50Ru50/Ti at 55% compared to Pt/Ti and commercial Pt/C.