Ru Single-Atom Decorated Black TiO2 Nanosheets for Efficient Solar-Driven Hydrogen Production

Solar-driven hydrogen production is an ideal way to fundamentally solve energy and environmental issues to some extent. TiO2 as a class of promising photocatalysts has attracted intensive attention. However, low light utilization and serious recombination of photo-induced charge carriers lead to a low efficiency. Herein, black TiO2 (B-TiO2) nanosheets have been first synthesized by H-2/Ar plasma treatment, onto which Ru single atoms are anchored by dipping RuCl3 solution. X-ray absorption fine spectra reveal that the Ru-O coordination number is similar to 5 from the scattering between the Ru center and O atoms of B-TiO2, demonstrating the strong interplay between Ru atoms with TiO2. Density functional theory (DFT) simulations and photoelectrochemical tests clarify that the introduction of Ru single-atoms produces impurity levels, which serves as charge-trapping sites, and facilitates the photo-generated electron separation and transportation. Furthermore, the Gibbs free-energy of the adsorbed H* over Ru-SAs/B-TiO2 is much closer to zero compared to that of pristine TiO2, thus considerably boosting the photocatalytic performance. The hydrogen evolution over Ru-SAs/B-TiO2 reaches 17.81 mmol/g/h with an apparent quantum efficiency (AQE) of 21.3% at 365 inn. It is expected that this facile strategy can be employed to fabricate other efficient photocatalysts for new energy production and environmental remediation.

Automated summary

This study presents a facile strategy to improve the photocatalytic performance by synthesizing black TiO2 nanosheets and anchoring Ru single atoms on its surface. The introduction of Ru single atoms creates impurity levels, facilitating the separation and transportation of photoelectrons, and significantly enhances the efficiency of hydrogen production.