Interface Engineering with Ultralow Ruthenium Loading for Efficient Water Splitting

Developing high-performance and cost-effective bifunctional electrocatalysts for water splitting is the key to large-scale hydrogen production. How to achieve higher performance with a lower amount of noble metal is still a major challenge. Herein, using a facile wet-chemistry strategy, we report the ultralow amount loading of ruthenium (Ru) on porous nickel foam (NF) as a highly efficient bifunctional electrocatalyst for water splitting. Theoretical simulations reveal that the coupling effect of Ru and Ni can significantly reduce the d-band center of the composite. The Ru-modified NF exhibits a very high level of HER activity with only 0.3 wt% of Ru, far surpassing commercial Pt/C. It only requires an extremely low overpotential (η₁₀) of 10 mV to achieve a current density of 10 mA cm^-2 in alkaline solution and a quite low Tafel slope of 34 mV dec^-1. This catalyst also shows remarkable performance for overall water splitting with a low voltage of 1.56 V at 10 mA cm^-2. These findings indicate the potential of this material in water-alkali electrolyzers, providing a new approach for fabrication of low-cost advanced electrocatalysts.