Engineering Partially Oxidized Gold via Oleylamine Modifier as a High-Performance Anode Catalyst in a Direct Borohydride Fuel Cell.

Abstract

Direct borohydride fuel cell (DBFC) is considered a promising energy storage device due to its high theoretical cell voltage and energy density. For DBFC, an Au catalyst has been used as an anode for achieving an ideal eight-electron reaction. However, the poor activity of the Au catalyst for borohydride oxidation reaction (BOR) limits its large-scale application because of the weak BH4- adsorption. We found, by density functional theory calculations, that the adsorption of BH4- on the oxidized Au surface is stronger than that on the metallic Au surface, which can promote the process of the oxidation of BH4- to *BH3 during the BOR. Here, we reported an oleylamine-modified partially oxidized Au supported on carbon powder (AuC-OLA) with a stable oxidation state. The obtained catalyst delivered a high peak power density of 143 mW/cm2, which is 2 times higher than that of a commercial 40% AuC (Pretemek). The in situ Fourier transform infrared studies showed that the activity of AuC-OLA for BOR is ascribed to the enhanced adsorption for BH4- on the partially oxidized Au surface. These findings will promote the reasonable design of efficient Au electrocatalysts for DBFCs.