Nanosphere-structured composites consisting of Cs-substituted phosphotungstates and antimony doped tin oxides as catalyst supports for proton exchange membrane liquid water electrolysis

Proton exchange membrane liquid water electrolyser operated blow 80 °C suffers from insufficient catalyst activity and durability due to the slow oxygen evolution kinetics and poor stability. Aiming at enhancing oxygen electrode kinetics and stability, composite materials consisting of antimony doped tin oxide and Cs-substituted phosphotungstate were synthesized as the support of iridium oxide and possessed functionality of mixed electronic and protonic conductivity. At 80 °C under dry ambient atmosphere, the materials showed an overall conductivity of 0.33 S cm−1. The supported IrO2 catalysts were characterized in sulfuric acid electrolyte, showing significant enhancement of the oxygen evolution reaction (OER) activity. Electrolyser tests of the catalysts were conducted at 80 °C with a Nafion membrane. At an IrO2 loading of 0.75 mg cm−2 and a Pt loading of 0.2 mg cm−2, the cell performance of a current density of 2 A cm−2 at 1.66 V was achieved. The cell showed good durability at 35 °C under a current density of 300 mA cm−2 in a period of 464 h.