Charge separation behaviors of novel AgI/BiOI heterostructures with enhanced solar-photocatalytic performance

The photocatalytic efficiency of the bare BiOI has been greatly restricted because of the high recombination rate of electron-hole charge pairs. To further regulate the photocatalytic performance of BiOI, in this work AgI was employed to couple with BiOI. A serial of novel AgI/BiOI heterostructures with improved sunlight-driven photocatalytic activities were prepared in-situ by a hydrothermal method. The results reveal that the presence of AgI in the composites alters band gap of the samples and greatly affects the photo-induced charge separation rate benefited from the strong interaction between AgI and BiOI. ·OH and ·O2− were observed using electron spin-resonance (ESR) spectroscopy. The photocatalytic activities of AgI/BiOI heterostructures for the decay of methyl orange (MO) and phenol solution under the simulated sunlight irradiation were investigated, the results display that the composite photocatalysts exhibit higher photocatalytic activity than the bare BiOI and excellent stability. The charge separation and transfer mechanism was proposed based on the experimental results.