Impregnated Electroreduced Pt on Ru/C as an Anode Catalyst for Direct Methanol Fuel Cells

Abstract

Direct methanol fuel cells (DMFC) have attracted considerable attention as an alternative energy source for portable devices due to their advantages of relatively higher energy densities and easy fuel storage. The successful commercialization of DMFC depends heavily on the activity and durability of the electrocatalysts. Pt-Ru nanoparticles supported on carbon are a well-studied anode electrocatalyst for DMFC due to their efficient CO removal ability. In this work, we propose a method for synthesizing Pt on ruthenium-on-carbon support (Pt/RuC) by combining the polyol and impregnation-electroreduction methods. First, ruthenium-on-carbon support (Ru/C) with varying Ru weight percentages (viz. 8, 17, and 30 wt%) was synthesized via the polyol process using ethylene glycol as a reducing agent. Second, Pt was impregnated on Ru/C-coated carbon paper and subsequently electroreduced using square wave pulse deposition. Using this synthesis method produced a smaller and more uniform Pt particle size distribution compared to the conventional electroreduction method. Of the various compositions of the Pt/RuC catalyst synthesized, Pt deposited on 30 wt% Ru/C revealed the highest electrochemical surface area and increased mass activity for methanol oxidation reaction. The anode catalyst, when tested in a DMFC, showed the highest peak power density of 80 mW cm−2 at 80°C. Additionally, a short-term stability test carried out at 100 mA cm−2 for 10 h revealed the superior stability of the electrocatalyst.