PtCo/rGO nano-anode catalyst: enhanced power density with reduced methanol crossover in direct methanol fuel cell

Abstract

The higher methanol utilization efficiency in direct methanol fuel cell (DMFC) is one of the key factors that determine the performance of DMFC. Herein, we have synthesized bimetallic PtCo nano-particles (with optimized Pt:Co ratio) decorated reduced graphene oxide (rGO) nano-composite as anode catalyst. The electrochemical response of optimized PtCo (1:9)/rGO catalyst revealed efficient oxidation of 5 M methanol in half-cell configuration with ~ 60% Faradaic efficiency. A current density of 463.5 mA/cm2 and a power density of 136.8 mW/cm2 were achieved using PtCo (1:9)/rGO anode catalyst in a complete DMFC set-up at 100 °C with 5 M methanol supply which is ~ three times greater as compared to commercial Pt/C (48.03 mW/cm2). The low activation energy of 9.88 kJ/mol indicates the faster methanol oxidation reduction (MOR) kinetics of PtCo (1:9)/rGO anode catalyst. Furthermore, the higher methanol utilization and open-circuit voltage in complete DMFC using PtCo (1:9)/rGO as compared to commercial Pt/C indicate the reduced methanol crossover. The excellent catalytic behavior of PtCo (1:9)/rGO towards MOR and high methanol utilization warrant its potential application as anode catalyst in DMFC.