Fabrication of 2D/2D Z-scheme highly crystalline carbon nitride/δ-Bi2O3 heterojunction photocatalyst with enhanced photocatalytic degradation of tetracycline

Photocatalytic degradation of antibiotic pollutant from contaminated water is essential for environmental protection. Rational development and design of composite photocatalyst with high catalytic activity and stability plays an important role in the photocatalytic field. Herein, 2D/2D highly crystalline carbon nitride/δ-Bi2O3 (HCCN/BO) Z-scheme heterojunction photocatalyst was synthesized via a facile solvothermal strategy. Experimental results show that the optimal HCCN/BO-3 sample exhibits a ~ 90% degradation rate during the photocatalytic degradation of the tetracycline (TC) within 60 min. The enhancement of photocatalytic activity is mainly attributed to the two reasons as follows: (i) the formation of 2D/2D heterojunction shortens the distance of the carriers from the body to the surface and gives two kinds of semiconductors rich active sites, improving the production and separation efficiency of photogenerated active carriers; (ii) the transmission path of photo-induced electrons follows the Z-scheme that can effectively inhibit the recombination of electrons and holes, expand the wide band gap, and harvest more visible light, separate oxidation and reduction active sites to retain redox capacity. Finally, the intermediate in the degradation pathway is determined using liquid chromatography-series mass spectrometry (LC-MS), and the TC degradation pathway for the photocatalytic reaction process of this composite system is proposed.