Cr and Nd co-doped cobalt oxide for stable proton exchange membrane water electrolysis

Developing noble-metal-free electrocatalyst for oxygen evolution reaction in a proton exchange membrane water electrolyzer is a key to sustainable and economical hydrogen production. Herein, we rationally design and develop a chromium and neodymium co-doped cobalt oxide (CrNd-Co₃O₄) electrocatalyst that exhibits high activity and durability in the acidic oxygen evolution reaction condition. Furthermore, an in-situ acid circulation strategy is proposed to tackle the ubiquitous issue of membrane poisoning by leached cations in proton exchange membrane water electrolyzers. Consequently, the proton exchange membrane water electrolyzer with CrNd-Co₃O₄ anode achieves a stable operating current density of 2 amperes per square centimeter at 2.27 volts and 4 amperes per square centimeter at 2.54 volts for 1,000 hours.