Catalytic Interface of rGO-VO₂/W₅O₁₄ Hydrogel for High-Performance Electrochemical Water Oxidation

The continuous increase in global energy demand necessitates the development of sustainable, clean, and highly efficient methods of energy generation. Electrochemical water splitting, comprising hydrogen evolution reaction (HER) and oxygen evolution reaction (OER), represents a promising strategy but remains hindered by sluggish reaction kinetics and limited availability of highly active electrocatalysts especially under alkaline conditions. Addressing this challenge, we successfully synthesized a rGO-VO₂/W₅O₁₄ (rG-VO₂/W₅O₁₄) hydrogel electrocatalyst through a facile hydrothermal approach. The prepared composite distinctly reveals an advantageous hierarchical microstructure characterized by VO₂ nanoflakes uniformly distributed on the surface of rGO nanosheets, intricately integrated with W₅O₁₄ nanorods. Evaluated in a 1.0 M KOH electrolyte, the optimized rG-VO₂/W₅O₁₄-2 catalyst demonstrates remarkable electrocatalytic performance towards OER, achieving a low overpotential of 265.8 mV and a reduced Tafel slope of 81.9 mV dec^-1. Furthermore, the catalyst maintains robust stability with minimal performance degradation, exhibiting an overpotential of only 273.0 mV after 5000 cyclic stability tests. The superior catalytic activity and durability are attributed to the synergistic combination of enriched chemical composition, effective electron transfer, and abundant catalytic active sites inherent in the well-optimized rG-VO₂/W₅O₁₄-2 composite.