Rational design 2D/2D BiOCl/H+Ti2NbO7− heterojunctions for enhanced photocatalytic degradation activity

Abstract

To realize highly efficient removal of organic pollutant is a hot spot in environmental and energy science. Herein, we firstly prepared re-stacked H+Ti2NbO7− nanosheets (HTN) to fabricate the novel two-dimensional (2D)-2D BiOCl/H+Ti2NbO7− (BHT) heterojunctions by a hydrothermal method. The HTN were well combined with BiOCl nanoplates with an intimate interface to form a heterostructure. The rhodamine B (RhB) molecules were used as a target pollutant to evaluate the photocatalytic performance of samples under visible light. All BHT composites, with an optimal sample of BHT-4, showed the improved photocatalytic activity for degradating RhB compared with the single BiOCl and HTN. The enhanced activity was mainly attributed to the efficient charge separation and transfer, which was resulted from the formation of heterojunction between BiOCl and HTN. The produced active species can be detected by trapping experiments and ESR spectra. It indicated that hole (h+) and superoxide radical (O2−) played a crucial role in the photocatalytic RhB degradation, while hydroxyl radical (OH) contributed a little. A possible photodegradation mechanism was also discussed based on the corresponding experimental results. This work provides an insight for preparing 2D/2D heterojunctions with a high photocatalytic activity.