Construction of novel 0D/2D AgI/CAU-17 heterojunction with excellent photocatalytic performance by in situ deposition-precipitation

Dye effluent is a serious threat to water ecosystem and human health, so it is urgent to develop high-efficient and stable semiconductor photocatalysts to solve the water pollution problem. A novel AgI/CAU-17 composite with 0D/2D hierarchical heterostructure was first constructed by growing AgI particles on CAU-17 nanorods via a mild deposition-precipitation procedure. The optimal 50% AgI/CAU-17 composite displayed the greatest photodegradation rate of 96.7% for RhB, 81.3% for TC and 50.3% for MO, under the simulated solar-light illumination for 70 min. The corresponding apparent rate constants were 0.04401, 0.02227 and 0.01104 min−1, which were 23.79, 15.25 and 19.73-times higher than those of CAU-17, and 4.94, 1.79 and 6.29-times higher than those of AgI. The improved photodegradation performance could be owing to the following causes: 1) The 0D/2D hierarchical heterostructure endowed AgI/CAU-17 composite with tight interfacial contact, which could supply sufficient channels for the migration of photoinduced carriers; 2) The type II charge migrate pathway facilitated the segregation and migration of photoexcited carriers; 3) The AgI/CAU-17 heterostructures reinforced the light absorption capacity and augmented the specific surface area. In addition, various photocatalytic conditions were researched to imitate the degradation process of RhB in the real aqueous system. The radical capture experiments and EPR test attested that h+ and •O2- played an important part in the photodegradation of RhB. This study illustrated the tremendous application potential of AgI/CAU-17 heterojunctions in water purification and provided a simple and reliable idea for the preparation of Bi-MOFs composite photocatalysts.