Crucial effect of rubidium cation on catalytic activity of a polycrystalline gold electrode toward oxygen reduction reaction in alkaline media

Abstract

Catalytic activity of a polycrystalline gold electrode toward oxygen reduction reaction (ORR) in aqueous alkaline media in the presence of various alkali-metal sulfates (M 2SO 4, M = Li, Na, K, Rb and Cs) was investigated by hydrodynamic voltammetry. The fraction of 4e − pathway in low overpotentials (− 0.1 to − 0.3 V) depended on the alkali-metal cations (Rb ≫ Na, K, Cs, Li). A complete 4e − reduction of O 2 was only attained in the presence of Rb + cation in the solution, which was comparable or even superior to that reported at the Au(100) single crystal electrode.