Cobalt-doped hexagonal molybdenum trioxide derived from polyoxometalate: a promising catalyst for overall water splitting†

This study presents the fabrication of cobalt atom-doped molybdenum trioxides using polyoxometalate as precursors, via a solution evaporation technique followed by an annealing process. By precisely controlling the annealing temperature, molybdenum trioxides were synthesized in both hexagonal and orthorhombic crystalline phases. This temperature-dependent phase transformation highlights the critical balance needed in the annealing process to tailor the structural properties of the resulting molybdenum oxide, thus achieving robust control over its crystallographic characteristics. Moreover, the cobalt-doped hexagonal molybdenum trioxides exhibit catalytic activity towards overall water splitting under alkaline conditions. This research introduces a novel design paradigm for utilizing polyoxometalate cluster-derived functional materials in electrocatalysis, enabling the systematic and rational design of advanced water electrolysis catalysts with exceptional performance.