Universal synthesis strategy for preparation of transition metal oxide electrocatalysts doped with noble metal single atoms for oxygen evolution reaction†

Electrochemical water splitting is expected to be a promising solution to the growing problem of fossil fuel depletion, but is limited by the slow anodic oxygen evolution reaction (OER). Currently, nanomaterials such as Ru/Ir-based noble metal compounds have been used as highly active electrocatalysts for OER, but the high cost and scarcity hinder their wide application. Therefore, it is crucial to develop OER electrocatalysts that combine economic efficiency with high catalytic performance. In this work, we propose a universal synthesis strategy for the preparation of various noble metals-doped 3d-transition metal oxides (NM-TMO) electrocatalysts by the salt-template method. Our characterization analyses demonstrate that the noble metals are homogeneously dispersed as single atoms in transition metal oxides. Notably, Ir-doped Co₃O₄ catalysts, with Ir content as low as 1.35 at% (Ir–Co₃O₄), exhibit excellent OER performance in acidic, alkaline, and neutral media, compared to commercial IrO₂ as well as undoped Co₃O₄. This work demonstrates that the synthesis method is applicable to a wide range of noble metals and 3d-transition metal oxide matrix. This method results in reduced costs by significantly decreasing the noble metal, but improving catalytic performance.