Abstract: The surface plasmonic resonance (SPR) effect of Bi can effectively improve the light absorption abilities and photogenerated charge carrier separation rate. In this study, a novel ternary heterojunction of g-C₃N₄/Bi₂MoO₆/Bi (CN/BMO/Bi) hollow microsphere was successfully fabricated through solvothermal and in situ reduction methods. The results revealed that the optimal ternary 0.4CN/BMO/9Bi photocatalyst exhibited the highest photocatalytic efficiency toward rhodamine B (RhB) degradation with nine times that of pure BMO. The DRS and valence band of the X-ray photoelectron spectroscopy spectrum demonstrate that the band structure of 0.4CN/BMO/9Bi is a z-scheme structure. Quenching experiments also provided solid evidence that the ·O^2- (at -0.33 eV) is the main species during dye degradation, and the conduction band of g-C₃N₄ is only the reaction site, demonstrating that the transfer of photogenerated charge carriers of g-C₃N₄/Bi₂MoO₆/Bi is through an indirect z-scheme structure. Thus, the enhanced photocatalytic performance was mainly ascribed to the synergetic effect of heterojunction structures between g-C₃N₄ and Bi₂MoO₆ and the SPR effect of Bi doping, resulting in better optical absorption ability and a lower combination rate of photogenerated charge carriers. The findings in this work provide insight into the synergism of heterostructures and the SPR absorption ability in wastewater treatment.

Key words: g-C₃N₄/Bi₂MoO₆/Bi, Z-scheme catalyst, Surface plasmonic resonance effect, Rhodamine B, Visible light