Co3O4|CoP Core–Shell Nanoparticles with Enhanced Electrocatalytic Water Oxidation Performance.

Developing high performance, cost-effective, and durable electrocatalysts that must be derived from non-noble metals is crucial for alkaline oxygen evolution reaction (OER). OER, which takes place at the anode, is accepted as a major obstacle for commercialization due to its sluggish kinetics. In this study, a two-step synthesis method, such as a hydrothermal process followed by the annealing of the reactants in an Ar-filled Swagelok cell, is briefly described to obtain a cubic type of Co₃O₄ core and CoP shell. As a result of synergy, Co₃O₄|CoP demonstrates an onset overpotential of 280 mV and reaches a current density of 10 mA cm^–2 at an overpotential of 320 mV in an alkaline medium (pH = 13.5). The electronic property of the heterojunction is verified by the Tauc plot and valence band XPS. The band structure indicates that Co₃O₄|CoP exhibits a more metallic character than pristine Co₃O₄ due to the fact that the charge transfer process is faster. Further, the introduction of CoP significantly modifies the redox processes of Co₃O₄, which we examined with the help of large amplitude alternating current voltammetry (LA-ACV). The mechanistic study suggests that "catalytic performance is directly related to the peak-to-peak current density" of the redox process of the combined catalyst and reactant. [ABSTRACT FROM AUTHOR]