Electrodeposited mesoporous platinum catalysts over hierarchical carbon monolithic support as anode in small PEM fuel cells

Abstract

A mesoporous platinum catalyst was electrodeposited on the outer region of a carbon with hierarchical porous structure, using a block copolymer template. The platinum deposits exhibit an excellent stability enhanced by the roughness of the carbon support. Membrane Electrode Assemblies (MEAs) were prepared using the hierarchical carbon supported mesoporous platinum as anode, a Nafion 117 membrane, and a commercial gas diffusion electrode on the cathode side. Their performance was compared with that of MEAs prepared with commercial gas diffusion electrode and electrodeposited mesoporous catalyst over carbon cloth, by measuring the polarization curves in a single fuel cell (1 cm2 active area) with H2/O2 at 60 °C and at ambient pressure. The fuel cell with mesoporous catalyst over hierarchical carbon reaches a power density of 25 mW mgPt−1 cm−2, 50% higher than that obtained with the commercial gas diffusion electrode. The high power density achieved is attributed to a synergic effect as a result of the integration of the structured catalyst and hierarchical carbon, which is proposed as an innovative procedure to prepare efficient MEAs for small fuel cells.