Saturated hydrogen regulated ti coordination of metallic tih2/ti electrode via in-situ electrochemical hydrogenation for enhanced hydrogen evolution reaction

The hydrogen adsorption energy is an important factor of hydrogen evolution reaction (HER) intrinsic catalytic activity. Herein, we propose a facile strategy to synthesize metallic titanium hydride (TiH2) via in-situ electrochemical hydrogenation of titanium oxide (TiO2) in acidic media. The saturated H tunes Ti coordination reduces the ΔGH* and resistance of TiH2, which improves the H coverage and accelerates the charge transfer. The obtained TiH2/Ti possesses the enhanced HER activity with large current density (1400 mA cm−2 at −1.13 V vs. RHE) and superstability (1350 mA cm−2 for 88 h). Furthermore, large-sized and porous TiH2/Ti is produced by laser to construct the TiH2/Ti||IrO2/Ti electrolyzer, which confirmed that the self-supporting electrode with gas diffusion channel was beneficial for water electrolysis. This work provides an universal method to regulate metal coordination through in-situ electrochemical hydrogenation for the enhanced HER activity.