Heterostructured BiOCl–LaOCl S-scheme composites with improved visible-light photocatalytic activity on Rhodamine B dye

Abstract

In this work, we report the synthesis of heterostructured BiOCl–LaOCl composites by using KCl as a source of chlorine and varying contents of LaOCl as raw materials in the presence of ethylene glycol at a temperature of 100 °C by using the solvothermal method. The prepared composites were characterized by X-ray diffraction, UV–Visible NIR spectroscopy, photoluminescence spectroscopy, SEM, TEM, EDX mapping, BET, and XPS analysis. TEM analysis revealed that the LaOCl particles were deposited on the surface of the BiOCl microspheres. The photo-efficiency of the BiOCl–LaOCl composite as photocatalyst was assessed by decomposing the Rhodamine B dye in an aqueous solution under irradiation from sunlight. The composite was found to have a higher rate of degradation of the dye solution than those of pure BiOCl and LaOCl semiconductors. The BiOCl–LaOCl‐1 composite exhibited the maximum catalytic activity of all the synthesized materials. The ability of the composite to degrade the dye was studied by using UV–Vis spectroscopy. The apparent rate of reaction of BiOCl–LaOCl‐1 was 0.1209 min−1, four and six times higher than those of BiOCl–LaOCl-2 and BiOCl, respectively. The results of the scavenger test revealed that the superoxide and hole radicals were mainly responsible for photodegradation. The high BET surface area of the composite also indicated enhanced photocatalytic activity.