Unexpected activity of palladium on vanadia catalysts for formic acid electro-oxidation

Direct formic acid fuel cells have been demonstrated as a viable power source, particularly for portable power applications. Palladium catalysts are quite active, but the activity of pure palladium nanoparticles decays slowly with time. In this paper, we examine the properties of palladium on various supports to see if the activity can be stabilized. It is found that catalytic films made by depositing a submonolayer of Pd on V, Mo, W, and Au foils show activity that is stable. Pd-V outperforms conventional Pt/Ru catalyst at 0.3 V vs. RHE by three orders of magnitude on a per mass precious metals basis, and by two orders of magnitude on a per exposed surface area basis. Evidently, palladium films on supports have unusual properties for formic acid electro-oxidation. (c) 2005 The Electrochemical Society.