Facile preparation of Yb3+/Tm3+ co-doped Ti3C2/Ag/Ag3VO4 composite with an efficient charge separation for boosting visible-light photocatalytic activity

A novel Yb3+/Tm3+ co-doped Ti3C2/Ag/Ag3VO4 composite with stable and robust photodegradation performance was synthesized by in-situ partially reduction along with hydrothermal strategy. In the composite, block like Ag3VO4 particles are self-assembled on the surface of 2D Ti3C2 MXene accompanied by partial reduction of Ag+ to Ag-0. Photodegradation results showed that the resulting Yb3+/Tm3+ co-doped Ti3C2/Ag/Ag3VO4 composite with optimal Yb/Tm proportion (Y/T:0.3/0.005) presented a boosting photocatalytic performance for degradation of tetracycline (TC) and organic dyes under visible light irradiation. The removal efficiency was 97% for TC in 20 min, 96% for rhodamine B in 25 min, and 99% for methylene blue in 20 min, which was higher than that of Ag/Ag3VO4 composite. As manifested by photoelectrochemical measurements, the enhanced photocatalytic performance of the Y/T:0.3/0.005 composite was attributed to the improved light absorption and excellent charge separation induced by the formation of intermediate energy states after co-doping Yb3+/Tm3+ ions. Meanwhile, the photocatalytic mechanism of the photocatalyst was also investigated through electron spin resonance (ESR) spectra and trapping experiments, which verified that the active species of h(+) and center dot O-2(-) play the important role for photodegradation of tetracyline and organic dyes.