Engineering Lattice Strain in Co-Doped NiMoO₄ for boosting Methanol Oxidation Reaction

Nickel-based molybdates have attracted considerable attention owing to their distinctive isomorphous structure. In this study, pristine NiMoO₄ and Co-doped Ni_1-xCo_xMoO₄ were synthesized and investigated for their electrocatalytic activity in methanol oxidation and methanol-assisted water splitting reactions. Through a comprehensive exploration of the structure-property relationship, it was found that the optimal coexistence of α and β molybdate phases, induced by Co doping, led to lattice strain and facilitated the presence of essential catalytic descriptors such as higher oxidation states of Ni and surface oxygen vacancies within the lattice. These factors contributed to the enhanced electrocatalytic activity of Ni_0.7Co_0.3MoO₄ in methanol oxidation and hydrogen evolution reaction. Detailed kinetic studies were conducted to further elucidate the mechanisms involved. Overall, these findings highlight the promising potential of Ni_0.7Co_0.3MoO₄ as an effective catalyst for electrochemical methanol upgrading in conjunction with water splitting, with implications for sustainable energy conversion technologies.