Self-assembled Ag₄V₂O₇/Ag₃VO₄ Z-scheme heterojunction by pH adjustment with efficient photocatalytic performance

Semiconductor heterojunction plays a pivotal role in photocatalysis. However, the construction of a heterojunction with a fine microstructure usually requires complex synthetic procedures. Herein, a pH-adjusted one-step method was employed to controllably synthesize Ag₄V₂O₇/Ag₃VO₄ heterojunction with a well-tuned 0D/1D hierarchical structure for the first time. It is noteworthy that the ordered stacking of vanadium oxide tetrahedron ( $V{O}_3^{-}$) guided by the pH value wisely realizes the in-situ growth of Ag₄V₂O₇ nanoparticles on the surface of Ag₃VO₄ nanorods. Furthermore, comprehensive characterization and calculation decipher the electronic structures of Ag₄V₂O₇ and Ag₃VO₄ and the formation of Z-scheme heterojunction, benefiting the visible light harvesting and carrier utilization. Such a new Ag₄V₂O₇/Ag₃VO₄ heterojunction exhibits remarkable photocatalytic activity and excellent stability. Complete degradation of Rhodamine B (RhB) can be achieved in 10 min by the Ag₄V₂O₇/ Ag₃VO₄ heterojunction under visible light irradiation, demonstrating an outstanding reaction rate of 0.35 min⁻¹ that is up to 84-fold higher than those of other silver vanadates. More importantly, this integration of synthesis technology and heterojunction design, based on the intrinsic crystal and electronic structures, could be inspiring for developing novel heterostructured materials with advanced performance.