SnO2 quantum dots decorated NiFe2O4 nanoplates: 0D/2D heterojunction for enhanced visible-light-driven photocatalysis

Abstract

Nowadays, the fabrication of visible-light-induced photocatalysts with efficient light absorption and higher charge separation with improved active sites has appeared as an effective strategy for the degradation of hazardous pollutants. In this study, novel quantum dots (QDs)-based semiconductor photocatalyst nanocomposites (NiFe2O4/SnO2) with various amounts of SnO2 QDs (SQDs) (5, 10, and 15 mg) were successfully constructed through a simple hydrothermal synthesis. The as-prepared nanocomposites were studied using several microscopic and spectroscopic techniques, and the results further confirmed the establishment of heterojunctions between NiFe2O4 and SQDs. The results of photocatalytic investigations showed that the synthesized heterostructured NiFe2O4/SQD photocatalysts displayed substantially improved catalytic efficiency for the degradation of rhodamine B (RhB) upon visible-light treatment. In particular, the NiFe2O4/SQD nanocomposite with 10 mg of SQDs achieved an RhB degradation of 98% upon visible-light treatment within 105 min. The improved catalytic activity of the heterostructured nanocomposite can be credited to the synergistic interactions between NiFe2O4 and SQDs. Furthermore, the p-n heterojunction between NiFe2O4 and SQDs enable the direct transfer of photoinduced electrons from NiFe2O4 to the SQDs, which could retard the recombination of electron–hole pairs and enhance the catalytic activity. A probable catalytic reaction mechanism for the improved degradation efficiency of RhB by NiFe2O4/SQD nanocomposites is also proposed.