One-Pot Synthesized Visible Light-Driven BiOCl/AgCl/BiVO(4) n-p Heterojunction for Photocatalytic Degradation of Pharmaceutical Pollutants

A novel enhanced visible light absorption BiOCl/AgCl/BiVO(4) heterojunction of photocatalysts could be obtained through a one-pot hydrothermal method used with two different pH solutions. There was a relationship between synthesis pH and the ratio of BiOCl to BiVO(4) in XRD planes and their photocatalytic activity. The visible light photocatalytic performances of photocatalysts were evaluated via degradation of diclofenac (DCFF) as a pharmaceutical model pollutant. Furthermore, kinetic studies showed that DCF degradation followed pseudo-first-order kinetics. The photocatalytic degradation rates of BiOCl/AgCl/BiVO(4) synthesized at pH = 1.2 and pH = 4 for DCF were 72% and 47%, respectively, showing the higher activity of the photocatalyst which was synthesized at a lower pH value. It was concluded that the excellent photocatalytic activity of BiOCl/AgCl/BiVO(4) is due to the enhanced visible light absorption formation of a heterostructure, which increased the lifetime of photo-produced electron–hole pairs by creating a heterojunction. The influence of pH during synthesis on photocatalytic activity in order to create different phases was investigated. This work suggests that the BiOCl/AgCl/BiVO(4) p-n heterojunction is more active when the ratio of BiOCl to BiVO(4) is smaller, and this could be achieved simply by the pH adjustment. This is a promising method of modifying the photocatalyst for the purpose of pollutant degradation under visible light illumination.