Ni-Au anodic nano-electrocatalyst for direct glucose fuel cells

Abstract

This study aims at the sequential assembling of a nickel oxide (NiOx: cauliflower-like nanostructure, 90 nm) and gold (Au; spherical, 95 nm in an average particle size) onto the GC surface nanocatalyst on a glassy carbon (GC) electrode (will be abbreviated as Ni-Au/GC) for the glucose electro-oxidation (GO); the principal anodic reaction in the direct glucose fuel cells (DGFCs). The charge of the Ni deposition on the GC surface (will be abbreviated as Ni/GC electrode) was initially optimized to obtain the highest catalytic activity toward GO which attained at (339.8 Ag-1) by applying 15 mC in the Ni deposition. Yet, the NiOx/GC could not maintain an enduring stability toward GO, which suggested a further modification with Au. Interestingly, this modification obviously improved the stability toward GO; sustaining the rate of current decay at the Ni-Au/GC catalyst much lower than that at the Ni/GC catalyst. After 1 h of continuous electrolysis, the current was 1.15 mA at the Ni-Au/GC electrode compared to 0.6 mA at the Ni/GC electrode (~ twofold higher).