Sm-doped g-C3N4/Ti3C2 MXene heterojunction for visible-light photocatalytic degradation of ciprofloxacin

A heterojunction of Sm-doped g-CN/TiCMXene(SCN/MX) was constructed via prepolymerization and solid mixture-calcination method.The modified g-CNpresented a hollow porous seaweed-like shape which can increase its specific area and active sites.In SCN/MX composite,the optical properties,no matter optical absorption ability or separation performance of photo-induced electrons and holes,were enhanced.Among them,Sm-doping may play an important role on transferring the photogenerated electrons to suppress their recombination,and TiCMXene would broaden light absorption and further improve the carrier migration efficiency.The SCN/MX presented higher photocatalytic degradation efficiency(> 99%) of cipro floxacin under visible light irradiation.The quenching experiments and electron spin-resonance spectroscopy confirmed that the dominated active materials were superoxide radical and holes.The degradation mechanisms of ciprofloxacin(CIP) over the SCN/MX were attacking of the active materials on the piperazine ring and quinolone ring,and the final products were CO,HO and F~-.