High‐Throughput Screening of Co‐Fe‐Ni Electrocatalysts for High‐Current‐Density Water Electrolysis

Abstract Developing oxygen evolution reaction (OER) catalysts with optimum composition and highly active catalytic centres is a challenge during electrode scale‐up. We show a selection strategy for the optimum composition of Co‐Fe‐Ni catalyst systems through a scanning droplet cell‐based high‐throughput screening on thin‐film materials libraries, followed by fabrication and testing of the selected compositions in the form of catalyst‐coated porous electrodes for the OER in alkaline media. The electrode with optimum composition (Co 17 Fe 25 Ni 58 _Ni foam) exhibits a high current density of 1 A cm −2 during water electrolysis at an operating potential of ∼1.9 V.