Monolayered Ru1/TiO2 nanosheet enables efficient visible-light-driven hydrogen evolution

Efficient visible-light-driven hydrogen evolution (VLD-HER) is the most desirable for utilizing solar energy, but it remains a significant challenge to fabricate advanced photocatalysts. Herein, we report on a single-atom ruthenium doped monolayered TiO2 nanosheet catalyst (Ru1/TiNS). Unlike pure TiO2 with no VLD-HER activity, Ru1/TiNS enables efficient H2 evolution with a mmol h−1 g−1 magnitude (4.81) under visible light, comparable to 8.95 mmol h−1 g−1 under full light spectrum. Various ex-/in-situ characterizations and theoretical calculations reveal that the single-atom Ru1 introduces an impurity energy level, allowing light absorption up to 700 nm, and an oxygen vacancy around Ru1 tends to be a charge trapping site, promoting rapid photogenerated electron separation and transportation. This study provides a promising catalyst-design strategy for high-efficiency hydrogen production using solar energy.