Activation of a Nickel-Based Oxygen Evolution Reaction Catalyst on a Hematite Photoanode via Incorporation of Cerium for Photoelectrochemical Water Oxidation.

There has been debate on whether Ni(OH) is truly catalytically active for the photo/electrocatalytic oxygen evolution reaction. In this report, we synthesized a Ni(OH) cocatalyst on a hematite photoanode and showed that, as has been proposed in other studies, the current density varies as a function of scan rate, which arises due to a photoinduced capacitive charging effect. We discovered that this photoinduced charging of Ni can be overcome by mixing cerium nitrate into the Ni precursor solution.