One-pot co-precipitation of enhanced visible light active BiOCl based photocatalysts: Characterization, mechanism and DFT modelling

Abstract

BiOCl, though being a promising photocatalyst for water pollutants degradation, its large band gap limits its efficiency to the ultraviolet region of light. To overcome this challenge, we employed a one-step simple coprecipitation method at room temperature to synthesize visible light responsive BiOCl based nanoflakes. Doping with biochar from pyrolyzed spruce wood led to an improvement in electronic and optical properties. BiOCl doped with pyrolyzed wood exhibited better photocatalytic degradation of diuron on account of the slower charge recombination, lower band gap and better charge transfer ability suggesting the formation of heterostructures in this case. Complete removal of diuron was obtained with pristine and doped BiOCl, however the kinetics of removal was twice higher for the doped BiOCl. Scavenger experiments revealed that the O2 − • radicals were responsible for the photocatalytic degradation. A study into the photothermal effect showed that BiOCl pyro converted the light irradiation energy into heat slightly more than the pristine BiOCl. This heat energy could further be utilized for the photon-heat energy and improved photocatalytic performance. Characterization of the spent materials showed that they maintained their crystallinity and functionality. These findings provide a lowcost approach to synthesize BiOCl materials active under visible light and efficient for environmental remediation.