In-situ growth of nonstoichiometric CrO_0.87 and Co₃O₄ hybrid system for the enhanced electrocatalytic water splitting in alkaline media

The development of electrocatalysts for electrochemical water splitting has received considerable attention in response to the growing demand for renewable energy sources and environmental concerns. In this study, a simple hydrothermal growth approach was developed for the in-situ growth of non-stoichiometric CrO_0.87 and Co₃O₄ hybrid materials. It is apparent that the morphology of the prepared material shows a heterogeneous aggregate of irregularly shaped nanoparticles. Both CrO_0.87 and Co₃O₄ have cubic crystal structures. Its chemical composition was governed by the presence of Co, Cr, and O as its main constituents. For understanding the role CrO_0.87 plays in the half-cell oxygen evolution reaction (OER) in alkaline conditions, CrO_0.87 was optimized into Co₃O₄ nanostructures. The hybrid material with the highest concentration of CrO_0.87 was found to be highly efficient at driving OER reactions at 255 mV and 20 mA cm⁻². The optimized material demonstrated excellent durability for 45 h and a Tafel slope of 56 mV dec⁻¹. Several factors may explain the outstanding performance of CrO_0.87 and Co₃O₄ hybrid materials, including multiple metallic oxidation states, tailored surface properties, fast charge transport, and surface defects. An alternative method is proposed for the preparation of new generations of electrocatalysts for the conversion and storage of energy.