Promoted Alkaline Hydrogen Evolution Reaction Performance of Ru/C by Introducing TiO2 Nanoparticles

Higher water dissociation (Volmer step) energy barrier leads to the sluggish alkaline hydrogen evolution reaction (HER) rate. Since hydrophilic TiO2 can reduce water dissociation barrier while the widely studied Ru has nearly zero hydrogen adsorption Gibbs free energy, the combination of TiO2 and Ru/C might collectively enhance Volmer and Heyrovsky/Tafel step and finally promote HER performance. Herein, Ru/C-TiO2 with average size of 3.6 nm for Ru was synthesized by a two-step process. It presented superior alkaline HER activity with eta(10) of 44 mV, better than that of Ru/C (107 mV), Pt/C (84 mV) and C-TiO2 with negligible activity. The prominent HER performance was due to synergistic effect between TiO2 and Ru, which greatly expedited water dissociation for intermediate hydrogen production and the following electrochemical hydrogen desorption for producing H-2. This work combines specific active sites for different elementary steps and then boosts alkaline HER performance, which provide a guide for designing efficient and stable HER electrocatalyst.