Elevating the Photocatalytic Performance of BiOCl by Promoting Light Utilization: From Co doping to the Microreactor

Abstract

Owing to its unique layered structure, BiOCl demonstrates high photocatalytic activity. However, its wide bandgap hinders the absorption of visible light. Doping modification is an effective method to expand the light absorption edge of photocatalysts by creating a doping energy level within the bandgap. Herein, Co as a variable valence element was used to dope the BiOCl nanosheets through a simple hydrothermal approach. As a result, the absorption edge of Co−BiOCl extends to the visible light region, and the photocatalytic performance was enhanced by 3.02 times. To overcome the shortcoming of photons being consumed easily in the bulk reactor, a planar microreactor was introduced to reduce the attenuation of light and accelerate the mass transfer. By comparison to the bulk reactor, a maximum of 15.3-fold additional activity promotion emerged. This work combines doping modification and reactor improvement to realize highly efficient photocatalysis in practical application.

Optimization and Parameter Investigation of the Planar Photocatalytic Microreactor

“…Depending on the different forms of photocatalysts, photocatalytic reactions can be divided into immobilized (i.e., photocatalyst attached to the surface of reactors) or suspended (i.e., photocatalyst dispersed in the target solution) forms. − In general, the immobilized form of photocatalysis eliminates the requirement to recycle photocatalyst powder, which is suitable for continuous and large-scale photocatalytic reactions. − However, compared to the suspended form, immobilized photocatalysis in a bulk reactor (e.g., beaker) limits the mass transfer rates, undermining the photocatalytic efficiency dramatically. − In order to elevate the mass transfer in immobilized photocatalysis, microreactors with various structures were introduced owing to their short distance for mass and photon transportation. , By comparison with bulk reactors, microreactors possess much smaller reaction spaces. It is well known that target molecules need to move through the solution before being absorbed on the surface of the photocatalyst.…”