Building monolayer Ti0.91O2 nanosheets to enhance hydrogen production for photocatalytic water splitting

Two dimensional (2D) nanosheet photocatalysts have received intensive attention for various incomparable advantages. However, fabricating single-atom-thick photocatalyst nanosheets remains challenging. In this work, we developed monolayer nanosheets of Ti_0.91O₂ photocatalysts via the hydrazine assisted hydrothermal exfoliation of multilayer nanosheets. The hydrazine hydrate used for exfoliation can simultaneously serve as a sacrificial agent. Thepristine monolayer Ti_0.91O₂ photocatalysts achieved a hydrogen production rate of 6.22 mmol h⁻¹ g⁻¹ from water splitting, representing a fourfold enhancement over multilayer nanosheets. Upon loading Pt nanoparticles, the hydrogen production activity of Ti_0.91O₂ monolayer nanosheets increased to 13.28 mmol h⁻¹ g⁻¹. The monolayer nanosheets of Ti_0.91O₂ photocatalysts markedly enhanced the separation efficiency of photogenerated charge carriers. Furthermore, we demonstrate that the photogenerated electrons migrate to the edge of Ti_0.91O₂ monolayer nanosheets for the reduction reaction, while the photooxidation occurred on the surface of the nanosheets. This study provides valuable insights into the design of nanosheet photocatalysts.