Photocatalytic degradation of ranitidine and reduction of nitrosamine dimethylamine formation potential over MXene–Ti3C2/MoS2 under visible light irradiation

Photocatalysis is an effective method to degrade ranitidine (RAN), which is a typical precursor of nitrosamine dimethylamine (NDMA), an extremely potent human carcinogen. Herein, MXene-Ti3C2/MoS2 composites were prepared by a hydrothermal treatment aiming to use them for the photocatalytic degradation of RAN and the reduction of NDMA formation potential (NDMA-FP) under visible light irradiation for the first time. The analysis of the morphology, chemical composition and structure of these composites as well as the results of electrochemical experiments showed that a heterojunction was formed between MoS2 and Ti3C2, which facilitated the separation of electron-hole pairs and charge transfer, and thereby the photocatalytic performance. The MXene-Ti3C2/MoS2 composite (MT-4) exhibited the best photocatalytic performance in 60 min, with the highest RAN degradation and mineralization efficiencies of 88.4% and 73.58%, and the lowest NDMA-FP of 2.01%. Active species, including •O2- radicals, h+ and •OH radicals, all contributed to the degradation of RAN, among which •OH radicals were the main active species involved in the photocatalytic activity. The mechanism of the photocatalytic degradation of RAN over MXene-Ti3C2/MoS2 photocatalyst under visible light irradiation was proposed. This work opens up a new perspective on the applications of MXene-based materials for photocatalytic degradation of challenging pollutants.