Novel p–n heterojunction BiOI/CeO2 photocatalyst for wider spectrum visible-light photocatalytic degradation of refractory pollutants

Abstract

Recently, visible-light-driven photocatalysts have been widely used in environmental pollutant remediation. In the present study, BiOI/CeO₂ p–n junction photocatalysts were successfully fabricated using a facile in situ chemical bath method. The BiOI/CeO₂ p–n junction photocatalysts exhibited excellent photoactivity for the decomposition of the refractory pollutant bisphenol A (BPA) and methylene orange (MO) under visible light illumination. The sample with a 1 : 1 mole ratio of BiOI : CeO₂ possessed the highest photocatalytic performance out of all of the as-obtained catalysts. Mott–Schottky plots indicated that p–n junctions were successfully constructed between BiOI and CeO₂. The optical and electrical properties of the materials demonstrate that the introduction of BiOI can broaden the visible-light absorption region of CeO₂, and the transfer rate of the electron–hole pairs dramatically improves through forming a p–n junction. Furthermore, the BPA degradation efficiency exhibited excellent photostability after four consecutive cycles. These features show that the BiOI/CeO₂ p–n junction has great application potential for refractory pollutant removal from wastewater.