In-situ implantation of BiVO4 QDs into NH2-mil-125 to construct Z-scheme heterojunction for photocatalytic degradation of organic pollutants in water

Abstract

Organic pollutants in water seriously destroy the ecological environment and endanger human health. The photocatalyst composed of a metal-organic framework (MOF) and quantum dots (QDs) allows stable and efficient degradation of organic pollutants. A novel BiVO4 QDs/NH2-MIL-125 (BM) photocatalyst has been prepared by depositing of BiVO4 QDs in the Ti-based MOF (NH2-MIL-125(Ti)). The results indicate that the BiVO4 QDs/NH-MIL-125 sample has a porous structure with a concentrated pore size distribution and a large specific surface area. The decoration of BiVO4 QDs effectively broadens the optical response range of NH2-MIL-125 (NM). It is worth noting that 1%BiVO4 QDs/NH2-MIL-125 displays high photocatalytic activity in the degradation of 30 mg/L Rhodamine B (RhB) solution, and the degradation rate constant is 2.337 × 10−2 min−1, which is 4.2 and 5.4 times higher than NH2-MIL-125 and BiVO4 QDs, respectively. In the process of degrading RhB, h+ and ⋅O2− play the major roles in the RhB degradation. The construction of heterojunction between BiVO4 QDs and NH2-MIL-125 is favorable for photogenic carrier migration and inhibits electron and hole recombination. In addition, proposed a Z-Scheme reaction mechanism based on the band potential, where the structure favors carrier migration without photoelectron energy loss. This work is expected to promote the QD-MOF composites in water treatment.