Discovery of New Oxygen Evolution Reaction Electrocatalysts by Combinatorial Investigation of the Ni–La–Co–Ce Oxide Composition Space

We report a new family of earth-abundant electrocatalysts for the oxygen evolution reaction (OER) discovered via high-throughput screening of 1771 discrete metal oxide compositions covering the nickel–lanthanum–cobalt–cerium composition space. The catalytic performance of each of these compositions was measured under conditions applicable to distributed solar fuel generation using a three-electrode scanning-drop electrochemical cell. These high-throughput measurements show enhanced activity for catalyst compositions containing 20–65 metal atom % Ce. The catalytic activity and stability of a representative highly active composition (Ni_(0.1)La_(0.1)Co_(0.3)Ce_(0.5))O_x was verified by standard rotating-disc electrochemistry. Catalysts of this composition showed stable operational performance at 10 mA cm^(−2) for 2 h and survived a 100 h endurance test in a testbed electrolyzer