Tailor Control of Neodymium Doping Sites in γ‐MnO2 for Stable Oxygen Evolution Reaction in Acidic Electrolyte

Abstract

Large‐scale application of proton exchange membrane (PEM) water electrolysis for green hydrogen production is greatly limited by the cost and availability of precious metal catalysts (mainly Iridium‐based). Therefore, it is necessary to develop efficient, cost‐effective oxygen evolution reaction (OER) electrocatalysts for the replacement of Ir. In this study, the introduction of 1 mol% Neodymium (Nd) into γ‐MnO2 is found to extend the lifetime of γ‐MnO2 to ≈1000 h at 100 mA cm−2 in acidic electrolyte without loss of activity. The extension of catalyst lifetime is attributed to an increase in the dissolution potential of MnO4− by 50 mV, as indicated by in situ UV–vis spectro‐electrochemical measurements. Density functional theory (DFT) calculations suggest that Nd atoms are preferentially doped into the edge‐sharing Mn octahedral in ramsdellite phase, resulting in optimized binding energy between the catalyst and the oxygen intermediates. This work demonstrates that Nd element doping can modulate electronic structures to improve the catalytic stability of Mn‐based OER catalysts, highlighting the possibility of using earth‐abundant OER catalysts for PEM water electrolysis.