Electron-Conducting Perovskites As Oer Electrocatalysts in Alkaline Medium

Hydrogen is an attractive energy carrier and electrolysis of water is an important route to hydrogen generation. Alkaline water electrolysis is preferred over electrolysis in acidic medium due to the possibility of lowering stack costs and enhancing he library of stable electrocatalyst materials available for the electrochemical reactions. The high anode overpotential arising from the sluggish oxygen evolution reaction (OER) has led to significant interest in developing stable and active OER electrocatalysts. IrO2 (state of the art catalyst), RuO2 and PGM-based pyrochlores are suitable catalyst materials that exist today, but there is benefit in finding cost-effective alternatives. In this study, perovksite oxides of the form La[Ni(1-x-y)CoxFey]O3 (where 0≤x≤1 and 0≤y≤1) were synthesized by the co-precipitation method. Many of these perovskites exhibited electron conductivities greater than 0.1S/cm, eliminating the need to add carbon for OER studies and implying the likelihood of making conducting electrodes without additives with these materials. The electrocatalytic activity for the OER was studied using a rotating disk electrode (RDE) in 0.1M KOH. A decrease in OER activity was observed with increasing cobalt content in perovskites with y=0. A similar trend was observed for perovskites containing iron with x=0. All the perovskite electrocatalysts exhibited higher onset overpotentials than state-of-the-art-IrO2 but many exhibited significantly higher specific activities than IrO2 at 1.6V vs RHE. Specific activities of 0.21 A/m2, 7.08 A/m2 and 1.01 A/m2 at 1.6V vs RHE and 0.05 A/m2, 0.1 A/m2 and 0.07 A/m2 at 1.5V vs RHE were obtained for IrO2, LaNi0.6Co0.4O3 and LaNi0.6Fe0.4O3 respectively.