Oxygen evolution reaction catalyst and method for its preparation

Abstract

A process for preparing a catalyst, as well as a catalyst, the catalyst comprising an oxygen evolution reaction electrocatalyst OER, a hydrogen oxidation reaction HOR electrocatalyst, and a particulate solid support are described. The OER electrocatalyst and the HOR catalyst are both supported on the particulate solid support. The OER is deposited from an aqueous mixture comprising a particulate solid support and a halide free metalate which comprises iridium and / or ruthenium. The pH of the mixture is reduced to ≤7 to precipitate the oxygenated metal into the solid particulate support. In the process, the OER electrocatalyst is deposited before the HOR electrocatalyst. The catalyst may be incorporated into a catalyst coated membrane (CCM) and used in a fuel cell. [Figure 1a]