Self-terminated Electrodeposition of Iridium Electrocatalysts

Published

September 16, 2015

Author(s)

Thomas P. Moffat

Abstract

A simple electrochemical process for submonolayer deposition of ultrathin catalytic iridum (Ir) films is demonstrated. The process enables effective utilization of one of nature’s rarest elements while different substrates facilitate the exploration of bimetallic catalysis required for a sustainable hydrogen economy. Semi-coherent Ir films were deposited on Au, Pt and Ni substrates using a K3IrCl6-H2SO4 electrolyte operated between 40°C and 70°C. However, the deposition reaction is quenched at the onset of H2 production where adsorbed H blocks the reduction of IrCl6-xH2Ox3-x to Ir. The electrode can be reactivated for further deposition by pulsing the potential to more positive values where adsorbed H is oxidized. The electrocatalytic activity of ultrathin Ir and Pt films, and combinations thereof, were examined as function of the number of self-terminating deposition pulses. The ultrathin films match or exceed the best reported activity metrics for hydrogen oxidation in alkaline media and water splitting in acid.

Citation

Nature Materials

Pub Type

Journals

Keywords

Iridium, Electrodeposition, water splitting, self-terminated deposition, atomic layer deposition

Citation

Moffat, T. (2015), Self-terminated Electrodeposition of Iridium Electrocatalysts, Nature Materials (Accessed April 26, 2024)