Synthesis of RuO₂-Co₃O₄ Composite for Efficient Electrocatalytic Oxygen Evolution Reaction

Among various H₂ production methods, splitting water using renewable electricity for H₂ production is regarded as a promising approach due to its high efficiency and zero carbon emissions. The oxygen evolution reaction (OER) is an important part of splitting water, but also the main bottleneck. The anodic oxygen evolution reaction (OER) for water electrolysis technology involves multi-electron/proton transfer and has sluggish reaction kinetics, which is the key obstacle to the overall efficiency of electrolyzing water. Therefore, it is necessary to develop highly efficient and cheap OER electrocatalysts to drive overall water splitting. Herein, a series of efficient RuO₂-Co₃O₄ composites were synthesized via a straightforward three-step process comprising solvothermal synthesis, ion exchange, and calcination. The results indicate that using 10 mg of RuCl₃·xH₂O and 15 mg of Co-MOF precursor in the second ion exchange step is the most effective way to acquire the Co₃O₄-RuO₂-10 (RCO-10) composite with the largest specific area and the best electrocatalytic performance after the calcination process. The optimal Co₃O₄-RuO₂-10 composite powder catalyst displays low overpotential (η₁₀ = 272 mV), a small Tafel slope (64.64 mV dec^-1), and good electrochemical stability in alkaline electrolyte; the overall performance of Co₃O₄-RuO₂-10 surpasses that of many related cobalt-based oxide catalysts. Furthermore, through integration with a carbon cloth substrate, Co₃O₄-RuO₂-10/CC can be directly used as a self-supporting electrode with high stability. This work presents a straightforward method to design Co₃O₄-RuO₂ composite array catalysts for high-performance electrocatalytic OER performance.