Layered Ti3C2 MXene and silver co-modified g-C3N4 with enhanced visible light-driven photocatalytic activity

Novel Ag/g-C3N4/Ti3C2 heterojunction (ACN/TC) was synthesized via one-step calcining the mixture of Ag+-melamine superamolecule and Ti3C2. With robust interfacial contact of ACN/TC heterojunction, the introduction of Ag nanoparticles could induce localized surface plasmon resonance and improve the visible light responsivity. Besides, layered Ti3C2 was served as electron sink and co-catalyst to provide rapid charges transfer channel and enhance O-2 adsorption, thereby accelerating the separation of photogenerated charges and production of radicals. The optimized ternary heterojunction (ACN/TC-15) exhibited that the photocatalytic removal rate of Rhodamine B (RhB) and Tetracycline hydrochloride (TC) reached 99.2% and 92.1% under visible light (lambda > 420 nm) irradiation, respectively. Besides, extending to lambda > 510 nm light irradiation, the removal rate of RhB and TC still 85.6% and 79.5%, respectively. During the TC degradation, the superoxide radical (center dot O-2(-)) was determined as the main oxidative species. Besides, the possible degradation pathway of TC was proposed. This work not only showed a simplified method for the preparation of Ag/g-C3N4/Ti3C2 composite, but also provided insights into Ti3C2 MXene as co-catalyst to improve the photocatalytic degradation of organic pollutants.