Pt-Ru Alloyed Fuel Cell Catalysts Sputtered from a Single Alloyed Target

This work illustrates the improved performance of a direct menthol fuel cell (DMFC) Pt_1-xRu_x alloy phase catalysts deposited via magnetron sputtering onto a carbon powder matrix from an alloyed mixed-metal target. The production of dispersed metal catalysts particles of the correct size, structure, bulk, and surface composition for effective methanol oxidation required extensive control of process parameters including sputter gas type, sputter gas concentration, deposition pressure, sputter power, and sputter type (RF or DC). Through the adjustment of these multivariate sputtering parameters, it was possible to make alloyed catalyst materials with varying crystallinity and composition ranging from Pt_0.32Ru_0.68 to Pt _0.50Ru_0.50. The careful balance of these parameters resulted in a low metal loading catalyst, ∼30 wt %, with a methanol oxidation reaction onset potential of <300 mV versus RHE and peak current of >200 uA/cm². The optimized sputtered catalysts have increased metal utilization and outperform commercially available catalysts at fuel cell operating potentials.