LaNi 4.5Al 0.5 alloy doped with Au used as anodic materials in a borohydride fuel cell

Abstract

Fuel cells using borohydride as the fuel have received much attention because of their high thermodynamic cell voltage. Using rare-earth hydrogen storage alloys as the anodic catalyst materials instead of noble metals showed high catalytic activity both in the electrochemical oxidation and the hydrolysis of borohydride. In this work, we doped Au to modify the surface structure of LaNi 4.5Al 0.5 alloy by a self-reduction reaction method. The surface of the alloy particles was evenly covered with Au after treatment. The largest discharge current density increased from about 150 mA cm −2 (discharge to −0.6 V versus Hg/HgO electrode) with the parent alloy to 250 mA cm −2 with the Au-doped alloy. This finding suggested that the electrochemical catalytic activity of the alloy was enhanced after modification with Au. Fuel utilization also increased after modification with Au.