Enhanced hydrogen evolution in neutral media via proximity effect of Ru/RuO2-TiO2 nanocatalysts

Ru-based nanomaterials have been demonstrated to be highly active electrocatalysts for hydrogen evolution reaction (HER), yet weak water adsorption and splitting ability in neutral media thus it is rather difficult for the intermediates to adsorb on the active site. Herein, we introduce a concept of the proximity effect, comprising adjacent Ru and RuO2 nanoparticles coupled on TiO2 (Ru/RuO2-TiO2), for the synergic promotion of water molecule adsorption and splitting, significantly enhancing HER electrocatalysis performance. The in-situ spectroscopy experiments and density function theory (DFT) simulations demonstrated that the proximity effect between the adjacent Ru nanoparticles and RuO2 nanoparticles can accelerate water adsorption and splitting. As a result, the as-made Ru/RuO2-TiO2 only need overpotentials of 52.7, 16.0, and 16.4 mV to achieve the current density of 10 mA cm–2 in neutral, acid, and alkaline media, respectively. The mass activity of Ru/RuO2-TiO2 in neutral media is 320 and 117 times higher than that of commercial Ru/C and Pt/C at the overpotential of 100 mV, respectively. This work emphasizes the proximity effect for activation of reactants which can be extended to other electrocatalytic reactions. © 2024