Boosting Hydrogen Evolution Reaction by Phase Engineering and Phosphorus Doping on Ru/P-TiO₂

Synergistic optimization of the elementary steps of water dissociation and hydrogen desorption for the hydrogen evolution reaction (HER) in alkaline media is a challenge. Herein, the Ru cluster anchored on a trace P-doped defective TiO₂ substrate (Ru/P-TiO₂ ) was synthesized as an electrocatalyst for the HER; it exhibited a commercial Pt/C-like geometric activity and an excellent mass activity of 9984.3 mA mg_Ru ^-1 at -0.05 V vs. RHE, which is 34.3 and 18.7 times higher than that of Pt/C and Ru/TiO₂ , respectively. Experimental and theoretical studies indicated that using a rutile-TiO₂ -crystal-phase substrate enhanced the HER activity more than the anatase phase. Rich surface oxygen vacancies on rutile-TiO₂ facilitated the adsorption and dissociation of water, while the partial substitution of Ti⁴⁺ with P⁵⁺ enhanced H₂ generation by facilitating hydrogen spillover from the Ru site to the surface P site, synergistically enhancing the HER activity.