Hydrogen Evolution Reaction on Gold Single-Crystal Electrodes in Acid Solutions

The hydrogen evolution reaction on the low index planes of single-crystal Au electrodes has been studied in HClO4 solutions with the aim of ascertaining the extent of the sensitivity of the reaction rate to the surface crystallographic structure. The use of the hanging meniscus rotating disk technique allowed to carry out all measurements under rotation, thus avoiding blocking effects produced by hydrogen bubbles and accumulation of dissolved hydrogen in the interfacial region during potential excursions into relatively high overpotentials. In contrast with previously published results showing only slight variations in activity with Au crystal face, a pronounced structural sensitivity is reported for the first time. The catalytic activity presents the following sequence Au(111) > Au(100) > Au(110).