Nanostructure catalysts prepared by multi-sputtering deposition process for enhanced methanol electrooxidation reaction

Abstract

We report size and/or composition-controlled nanostructure catalysts for direct methanol fuel cells fabricated by means of multi-sputtering deposition process. The size-controlled Pt nanophases ranging from 0.62 +/- 0.14 nm to 3.07 +/- 0.34 nm in average size with narrow size distribution are fabricated as a function of sputtering power ratio of targets. The composition-controlled PtRu alloy nanophases deposited at different RF power ratio of Pt and Ru targets with the same power of WO3 target exhibit varied atomic percentages of PtRu, i.e. (79.8:21.2), (62.2:37.8) and (37.6:62.4). Furthermore, the PtRu nanophases deposited at a constant RF power ratio of Pt and Ru targets with different power of WO3 target show controlled average sizes such as 3.62 +/- 0.15 nm, 1.86 +/- 0.23 nm, and 1.20 +/- 0.22 nm with the same compositions. The specific maximum power density of the nanostructure catalyst (similar to 100 W g(-1)) is superior to that of the conventional nanostructure catalyst (similar to 37 Wg(-1)), representing that the nanostructure catalyst has an excellent electrode structure for methanol electrooxidation as compared to the conventional catalyst. (c) 2012 Elsevier B.V. All rights reserved.