Synthesis of Ru_xIr_1-xO₂ Anode Electrocatalysts for Proton Exchange Membrane Water Electrolysis

Ru and Ir based materials were prepared by the thermal decomposition of polymeric precursor's method. The anode catalysts free from carbon substrate were obtained by tailoring the reaction process to avoid occurrence of CO₂ formation during water electrolysis. Various Ir contents were added in the Ru catalytic compositions for improving the oxidation-resistance of RuO₂ which was the best metallic oxide in H2O splitting. Their physical characterizations revealed the presence of agglomerates due probably to the heat treatment process consisting in the removal of organic carbon at 400 ºC. The prevalent existence of RuO2 and IrO2 in the anode materials was confirmed by XPS experiments and the electrochemical measurements enabled to show that Ru_xIr_1-xO₂ materials were more active towards water oxidation than IrO₂ catalyst. The O₂ evolution process started at 1.45 V with Ru_0.9Ir_0.1O₂ in the anodic compartment of a 25 cm² Proton Exchange Membrane Water Electrolyzer at 60ºC.