Gold-Supported Cerium-Doped NiO_x Catalysts for Water Oxidation

Abstract

The development of high-performance catalysts for the oxygen evolution reaction (OER) is critical for cost-effective conversion of renewable electricity to fuels and chemicals. Here we report the significant improvement in the OER activity of electrodeposited NiO x films resulting from the combined effects of using gold as a metal support and cerium as a dopant. This NiCeO x -Au catalyst delivers high OER activity in alkaline media, and is among the most active OER electrocatalysts reported to date. Based on theoretical modelling coupled with experimental observations, we ascribe the activity to a combination of electronic, geometric and support effects, where highly active under-coordinated sites at the oxide support interface are modified by the local chemical binding environment and by doping the host Ni oxide with Ce. The NiCeO x -Au catalyst is further demonstrated in a device environment by pairing it with a nickel-molybdenum hydrogen evolution catalyst in a water electrolyser, which delivers 50 mA consistently at 1.5 V over 24 hours of continuous operation. This work deepens the understanding of complex multi-component catalytic systems by showing how electronic, geometric and support effects can be combined to enhance catalytic activity.