Boosting Hydrogen Evolution Reaction by Phase Engineering and Phosphorus Doping on Ru/P-TiO 2 .

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 TiO 2 substrate (Ru/P-TiO 2 ) 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/TiO 2 , respectively. Experimental and theoretical studies indicated that using a rutile-TiO 2 -crystal-phase substrate enhanced the HER activity more than the anatase phase. Rich surface oxygen vacancies on rutile-TiO 2 facilitated the adsorption and dissociation of water, while the partial substitution of Ti 4+ with P 5+ enhanced H 2 generation by facilitating hydrogen spillover from the Ru site to the surface P site, synergistically enhancing the HER activity.