Sm-doped g-C_3N_4/Ti_3C_2 MXene heterojunction for visible-light photocatalytic degradation of ciprofloxacin

A heterojunction of Sm-doped g-C_3N_4/Ti_3C_2 MXene(SCN/MX) was constructed via prepolymerization and solid mixture-calcination method.The modified g-C_3N_4 presented 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 Ti_3C_2 MXene 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_2,H_2O and F~-.