Ag-enhanced CeF 3 -O: highly enhanced photocatalytic performance under NIR light irradiation.

CeF 3 -O with intermediate band showed improved synergic photodegradation activity toward HCl-TC and RhB under NIR light irradiation when enhanced by Ag as a cocatalyst. Ag + ions take electrons from the second transition in CeF 3 -O's intermediate band, which are then reduced to Ag as cocatalyst. The photodegradation efficiencies of HCl-TC by various Ag/CeF 3 -O nanoparticles in 180-min increase from 26.5 to 73.1%. The optimal Ag/CeF 3 -O-100 is about 2.76 times that of pure CeF 3 -O. Ag/CeF 3 -O-100 has an apparent rate constant of 4.5 × 10 -3  min -1 , which is 3.0 times that of pure CeF 3 -O. Similarly, Ag/CeF 3 -O-10 achieves a superior photodegradation efficiency of RhB at 96.7% under NIR light within 120 min. Its apparent rate constant of 27.7 × 10 -3  min -1 is 12.0 times that of pure CeF 3 -O (2.3 × 10 -3  min -1 ). Further, the turnover frequencies of Ag/CeF 3 -O nanoparticles are greatly higher than that of the corresponding pure CeF 3 -O nanoparticles. Ag-enhanced CeF 3 -O has a unique metal-semiconductor interface where Ag acts as a bridge for facilitating charge transfer and the separation efficiency of photogenerated carries. The synergic effect between CeF 3 -O and Ag provides a practical technique for enhancing the wastewater treatment with NIR light irradiation.