RuxNb1-xO2 catalyst for the oxygen evolution reaction in proton exchange membrane water electrolysers

Bimetallic catalyst system of ruthenium oxide (RuO₂) and niobium oxide (Nb₂O₅) was prepared using the Adams method and the hydrolysis method. Physical and electrochemical characterizations of the catalysts were studied using X-ray diffraction (XRD), Scanning electron microscopy (SEM), cyclic voltammogram (CV) and polarization measurements. Nb₂O₅ addition to RuO₂ was found to increase the stability of RuO₂. In Adams method the sodium nitrate was found to be forming complex with Nb₂O₅ at high temperature reaction. This makes Adams method unsuitable for the synthesis of RuO ₂-Nb₂O₅ bimetallic system. Hydrolysis method on other hand does not have this problem. But a proper mixture of two oxides was not obtained in hydrolysis method. A lower crystallite size for bimetallic system was obtained with Adams method compared to hydrolysis method. RuO ₂ prepared by Adams method had higher activity compared to the hydrolysis counterpart in electrolyzer operation with nafion membrane. A cell voltage of 1.62 V was obtained with RuO₂ (A) at 1 A/cm². A higher stability for Ru_0.8Nb_0.2O₂(A) compared to RuO₂(A) was observed in continuous cyclic voltammogram and electrolyzer cell test.