A Tandem 0D/2D/2D NbS₂ Quantum Dot/Nb₂O₅ Nanosheet/g-C₃N₄ Flake System with Spatial Charge–Transfer Cascades for Boosting Photocatalytic Hydrogen Evolution

The relatively high recombination rate of charges remains the most critical limiting factor for solar-driven water splitting for hydrogen generation. Herein, a tandem 0D/2D/2D NbS₂ quantum dot/Nb₂O₅ nanosheet/g-C₃N₄ flake (NSNOCN) system is designed. Owing to the unique spatial-arrangement and elaborate morphology of 0D NbS₂, 2D Nb₂O₅, and 2D g-C₃N₄ in the newly designed NSNOCN, plenty of spatial charge–transfer cascades from g-C₃N₄ to NbS₂ via Nb₂O₅ are formed to accelerate separation and transfer of charges significantly, thus contributing to a high photocatalytic H₂ generation rate of 13.99 mmol h⁻¹ g⁻¹ (an apparent quantum efficiency of 10.8% at 420 nm), up to 107.6 and 43.7 times by contrast with that of g-C₃N₄ and Nb₂O₅, respectively. This work can provide a new platform in the design of artificial photocatalytic systems with high charge–transfer efficiency.