Non-noble-metal TiC-nanoparticle-promoted charge separation and photocatalytic degradation performance on Bi2O3 microrods: degradation pathway and mechanism investigation

In the present work, a promising binary TiC/Bi₂O₃ photocatalyst was obtained via a simple hydrothermal route. In the photodegradation experiment of acid orange 7 (AO7) and tetracycline (TC) irradiated by simulated sunlight, the attachment of TiC nanoparticles on the Bi₂O₃ microrods leads to an obvious improvement in the photocatalytic removal properties of the Bi₂O₃ microrods. The optimal removal efficiency of AO7 was achieved by the 7.5%TiC/Bi₂O₃ sample, which results in about 91.5% dye removal within 75 min of reaction. Meanwhile, the 7.5%TiC/Bi₂O₃ sample also exhibits favorable photodegradation performance for the degradation of TC, leading to about ∼76.9% TC being degraded after 75 min of irradiation. More importantly, the degradation pathways of AO7 and toxicity analysis of the intermediate products were performed based on liquid chromatography-mass spectrometry detection and theoretical simulation. The superior photocatalytic behavior of the TiC/Bi₂O₃ composite is attributed to the effective separation and migration of photoexcited electrons and holes in the heterojunction, where the TiC nanoparticles act as an acceptor of photoexcited electrons.