Synergetic Ru-Co sites on oxygen-vacancy TiO₂ for accelerated water dissociation toward hydrogen production

Overcoming the sluggish water dissociation kinetics in alkaline media and seawater remains a critical challenge for scalable green hydrogen production, requiring the development of efficient water-splitting electrocatalysts. Here, we conducted an Ru-Co/TiO₂ catalyst, which features an oxygen-vacancy-rich titanium dioxide (TiO₂) support anchoring ruthenium (Ru) and cobalt (Co) species, for hydrogen evolution reaction (HER) in alkaline electrolytes. Comprehensive spectroscopic analyses reveal that the microwave-induced oxygen vacancies facilitate the effective anchoring and high dispersion of Ru-Co bimetallic sites while concurrently enhancing electronic interactions. This markedly reduces the kinetic barrier for water dissociation to adsorbed hydrogen intermediates and optimizes the hydrogen adsorption/desorption behavior, thereby synergistically boosting HER activity. Far surpassing its single-metal counterparts, the resulting Ru-Co/TiO₂ maintain stable operation for over 100 h, delivering remarkably low overpotentials at 10 mA cm^-2: 51 mV in 1.0 M KOH, 69 mV in alkaline seawater, and 293 mV in natural seawater. This work demonstrates general and scalable approaches that integrate support defect engineering with trace-level bimetallic modulation, providing valuable insights into the design of low-noble-metal, high-performance electrocatalysts for practical water and seawater electrolysis.