Interfacial fabrication of flower-like Bi-BDC-NH2/Ag2CO3 type II heterojunction for efficient visible light-driven Cr(VI) reduction

The interfacial compatibility of heterojunction photocatalysts critically governs the interaction modes between constituent materials. Herein, a flower-like Bi-BDC-NH 2 /Ag 2 CO 3 heterostructure was fabricated via a simple ion-exchange solution method, serving as a robust photocatalyst for the efficient photocatalytic reduction of Cr(VI) in simulated wastewater under visible-light irradiation. Ag 2 CO 3 nanosheets were in-situ grown on the surface of three-dimensional Bi-BDC-NH 2 , forming an Ag 2 CO 3 -on-Bi-BDC-NH 2 type II heterojunction that establishes intimate interfacial contact, significantly accelerating the charge and mass transport dynamics. In comparison with pure Bi-BDC-NH 2 and Ag 2 CO 3 , the optimal Bi-BDC-NH 2 /Ag 2 CO 3 -50 (with a weight ratio of 0.5:1) exhibited dramatically enhanced photocatalytic activity, achieving 99% Cr(VI) reduction within 2 hours under visible light (>420 nm, 150 W xenon lamp). Mechanistic investigations, including energy band structure analysis, radical trapping experiments, and photoelectrochemical measurements, revealed that the heterojunction interface significantly promotes the separation and transfer of photogenerated electron-hole pairs. This work provides valuable insights into the rational design of MOF-based heterojunction photocatalysts and their applications in environmental remediation.