Enhanced electroactivity of Pd nanocrystals supported on H3PMo12O40/carbon for formic acid electrooxidation

The preparation of highly dispersed precious metal catalysts is an important subject for fuel cell applications. Here, using a phosphomolybdic acid (PMo12)-assisted method, a Pd-PMo12/C catalyst with uniform Pd nanoparticles is prepared. The TEM results show that the presence of PMo12 facilitates the formation of uniform Pd particles with an average particle size of 3.2 nm. More importantly, the Pd-PMo12/C catalyst displays an enhanced activity and stability for formic acid electro-oxidation and a better tolerance toward CO poisoning than Pd nanocatalysts prepared with sodium citrate as a stabilizer. A combination of the composition and structure analyses show that the reasons for the improved electro-catalytic activity of the Pd-PMo12/C catalyst involve the metal-support interaction, the richer Pd oxide/hydrous oxide content and the inherent properties of PMo12. (C) 2012 Elsevier B.V. All rights reserved.