Ceria nanoparticles embedded in flower-like CoMoO4 nanostructures with rich oxygen vacancies for enhanced electrocatalytic oxygen evolution reaction

초록

Environmental issues like dwindling hydrocarbon reserves and the effects of climate change highlight an urgent need for sustainable energy alternatives. Electrochemical water electrolysis has become a prominent strategy to produce H2 and O2 from renewable sources, presenting significant energy generation potential. To enhance the sluggish kinetics of the oxygen evolution reaction (OER), it's crucial to develop electrocatalysts that are economical, efficient and reliable. The present study demonstrates the development of a unique CoMoO4/CeO2 composite through a facile two-step hydrothermal strategy followed by a calcination phase. The ceria nanoparticles are deliberately embedded into the voids of the hierarchical flower-like CoMoO4 structure, resulting in a remarkable enhancement in electrocatalytic activity. The CoMoO4/CeO2 nanocomposite demonstrated outstanding electrocatalytic performance, achieving an onset potential of 1.462 V and an overpotential of 232 mV vs RHE at a current density of 10 mA cm-2 in a 1.0 M KOH alkaline solution. This composite electrocatalyst maintained impressive electrocatalytic activity at a higher current density of 50 mA cm-2 as well. Additionally, a chronoamperometry analysis confirmed the remarkable stability of the CoMoO4/CeO2-20 nanocomposite over a 24 h period, showing minimal variation in current response. The combination of CoMoO4 and CeO2 in the composite catalyst creates a synergistic effect that increases the number of accessible electroactive sites, accelerates electron transfer kinetics, and enhances the interface between the electrode and electrolyte. As a result, the CoMoO4/CeO2 composite catalyst shows significant promise as a highly efficient electrocatalyst for electrochemical oxygen evolution reactions (OER).

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