Morphology Regulated Hierarchical Rods-, Buds-, and Sheets-like CoMoO₄ for Electrocatalytic Oxygen Evolution Reaction

Abstract

One of the hugely focused areas of research for addressing the world’s energy and environmental challenges is electrochemical water oxidation. Morphological modulation of nanomaterials is essential for producing efficient electrocatalysts to achieve the required results. The purpose can be achieved by controlling synthesis parameters, and this is a key factor which greatly influences the oxygen evolution reaction (OER) performance during electrochemical water splitting. In this study, synthesis of cobalt molybdate (CoMoO4) through a simple and low-cost hydrothermal/solvothermal strategy with tunable morphology is demonstrated. Different morphologies, namely rods-like, buds-like, and sheets-like, referred to as R-CMO, B-CMO, and S-CMO, respectively, have been obtained by systematically varying the solvent media. Their catalytic activity towards OER was investigated in 1.0 M aqueous KOH medium. R-CMO nanoparticles synthesized in an aqueous medium demonstrated the lowest overpotential value of 349 mV to achieve a current density of 10 mA cm−2 compared with other as-prepared catalysts. In contrast, the B-CMO and S-CMO exhibited overpotential values of 369 mV and 384 mV, respectively. Furthermore, R-CMO demonstrated an exceptional electrochemical stability for up to 12 h.

Keywords

• CoMoO₄ nanoparticles
• morphology evolution
• electrocatalyst
• oxygen evolution reaction