The band engineering of 2D-hybridized PCN-Sb2MoO6-Bi2O3 nanomaterials with dual Z-scheme heterojunction for enhanced photocatalytic water splitting without sacrificial agents

Abstract

Bi₂O₃ has broad application prospects in the field of photocatalysts. However, inevitable effects from the inherent properties of weak absorption under the visible light and easy recombination of photo-generated electrons and holes within Bi₂O₃ have meaningfully restricted their applications in photocatalysis researches. In this study, 2D Sb₂MoO₆ and 2D polymeric carbon nitride (PCN) were designed as the Z-scheme heterojunction in the construction of 2D-hybridized PCN/Sb₂MoO₆/Bi₂O₃ dual Z-scheme structure. The degradation rate and the efficiency of oxygen generation of the newly obtained specimen demonstrated an obviously large increase in comparison to the efficiency of Bi₂O₃ under visible-light condition. The remarkable photocatalytic activity of PCN/Sb₂MoO₆/Bi₂O₃ could be attributed to the promotion of visible-light absorption range and the effective separation of photo-generated carriers by the dual Z-scheme heterojunction, proved with DRS analysis and VASP calculation. The band structure of PCN/Sb₂MoO₆/Bi₂O₃ was built on experimental data and VASP theoretical calculation. A possible transfer path of charge carriers and the construction mechanism of the dual Z-scheme heterojunction were also proposed through this band structure. Our research provides a potential method to strengthen the visible-light absorption of photocatalytic materials with molybdate, illustrating the influences of heterojunctions in the enhancement of the separation of photo-generated carriers. It has a great guiding significance for the further analysis of photocatalytic water splitting oxygen evolution.