Boosting photo-charge transfer in 3D/2D TiO2@Ti3C2 MXene/Bi2S3 Schottky/Z-scheme heterojunction for photocatalytic antibiotic degradation and H2 evolution

Abstract

Herein, a novel 3D/2D TiO2@Ti3C2 MXene/Bi2S3 Schottky/Z-scheme heterojunction was successfully synthesized for tetracycline (TC) antibiotic photodegradation and H2 generation. For this purpose, the 1D sea urchin-like TiO2 nanoparticles and the 2D Bi2S3 nanosheets were evenly placed onto the 2D Ti3C2 nanosheets matrix through hydrothermal oxidation and electrostatic self-assembly route, respectively. Compared to the TiO2@Ti3C2 photocatalyst, the TiO2@Ti3C2/20% Bi2S3 heterojunction showed the maximum TC (40 mgL−1) photodegradation with an efficiency of 84.13% after 135 min of visible light irradiation. Moreover, the TiO2@Ti3C2/1% Bi2S3 sample achieved the highest H2 generation rate of 14141.23 μmolg−1h−1 (2.37 times higher than TiO2@Ti3C2) after 6h irradiation. The cycling findings showed no change in the photocatalytic activity of optimized sample, confirming its high stability and recyclability. Increased photocurrent density, reduced PL intensity, and reduced EIS arc further supported the lowered electro-hole pair recombination rate in the optimized TiO2@Ti3C2/Bi2S3 heterojunction. Radical trapping and band structure analysis indicated that the •O2− and •OH species are crucial to the photocatalytic process, pointing to a Schottky/Z-scheme heterojunction between TiO2 (n-type) and Bi2S3 (n-type). The increased surface area brought forth by this thoughtful design with the unique morphology results in more active sites to boost the photocatalytic effectiveness. Besides, the existence of Ti3C2 MXene as a Schottky barrier in this design could accelerate photo-charge separation/transport and improve light absorption. This research offers a potentially helpful concept for developing a multi-interface photocatalyst system with a strong redox capacity to create a healthy environment and renewable energy.