Design of 2D/2D heterojunction of Ti3C2/BiOClxBr1−x for enhancing photocatalytic performance

Newly emerged 2D metallic Ti3C2 is highly spotlighted for its unique properties and ubiquitous compounding compatibility. Herein we pioneeringly demonstrate a heterojunction photocatalyst of Ti3C2/BiOClxBr1−x. X-ray diffraction, scanning electron microscope, transmission electron scope, and X-ray photoelectron spectroscopy analysis indicates that BiOClxBr1−x is successfully in-situ grown upon Ti3C2 nanosheets. Visible light photocatalytic performance of 7 %-Ti3C2/BiOCl0.25Br0.75 is overwhelmingly superior to BiOClxBr1−x with an increment of 11.9 times in the reaction rate constant of RhB photodegradation, owing to the distinctive Schottky heterojunction between Ti3C2 and BiOClxBr1−x. UV–vis absorbance, photoluminescence, Fourier transform infrared spectra, Raman, electrochemical impedance spectra, and transient photocurrent response account for the improved utilization of visible light, effective separation of photogenerated carriers, and more photogenerated electron acceptors, which elucidate the superior photocatalytic performance and good stability of Ti3C2/BiOClxBr1−x. Trapping experiments and electron paramagnetic resonance tests verify that the dominant active species of·O2- and h+ are responsible for the rapid degradation of RhB. The reasonable photocatalytic mechanism of Ti3C2/BiOClxBr1−x is clarified based on the energy band structure and synergistic effect of the heterojunction. This work provides some novel insights into designing 2D layered heterojunction photocatalysts, boosting photocatalytic performance, and advancing Ti3C2 application.