Exceptional Photocatalytic Activities of rGO Modified (B,N) Co-Doped WO₃, Coupled with CdSe QDs for One Photon Z-Scheme System: A Joint Experimental and DFT Study

Artificial Z-scheme, a tandem structure with two-step excitation process, has gained significant attention in energy production and environmental remediation. By effectively connecting and matching the band-gaps of two different photosystems, it is significant to utilize more photons for excellent photoactivity. Herein, a novel one-photon (same energy-two-photon) Z-scheme system is constructed between rGO modified boron-nitrogen co-doped-WO₃, and coupled CdSe quantum dots-(QDs). The coctalyst-0.5%Rh_xCr₂O₃(0.5RCr) modified amount-optimized sample 6%CdSe/1%rGO3%BN-WO₃ revealed an unprecedented visible-light driven overall-water-splitting to produce ≈51 µmol h⁻¹ g⁻¹ H₂ and 25.5 µmol h⁻¹ g⁻¹ O₂, and it remained unchanged for 5 runs in 30 h. This superior performance is ascribed to the one-photon Z-scheme, which simultaneously stimulates a two photocatalysts system, and enhanced charge separation as revealed by various spectroscopy techniques. The density-functional theory is further utilized to understand the origin of this performance enhancement. This work provides a feasible strategy for constructing an efficient one-photon Z-scheme for practical applications.