Highly Enhanced Visible-light Photocatalytic Activity via a Novel Surface Structure of CeO2/g−C3N4 toward Removal of 2,4-dichlorophenol and Cr(VI)

Graphical The rule of seven : The brilliant photocatalytic performance of CN−OH/CeO 2 −NP is due to the synergistic improvement of surface structure. The heptazine ring of g−C 3 N 4 can establish a consummate complexing with K ion. Moreover, unsaturated-coordination O between CN−OH/CeO 2 −NP composite can establish a firmly interfacial interaction with g−C 3 N 4 nanosheets by p–π bond. Furthermore, the hydroxyl groups on the surface of ceria can form hydrogen bond with the NOH/NH x group of g−C 3 N 4 nanosheets. Photocatalysis is an efficient and eco-friendly method of solving the environmental problems, but the low charge separation efficiency of photocatalysts limits their application. Herein, we report the fabrication of CeO 2 /g−C 3 N 4 composites via an in-situ growth of CeO 2 on the dispersed g−C 3 N 4 sheets (CN−OH) in an strong KOH condition, and the resultant CeO 2 /CN−OH composites set up a new interface structure, which demonstrate a dramatically boosted the photocatalytic activity compared with CeO 2 /g−C 3 N 4 composites by conventional two-step combination method. The decomposition efficiency of CeO 2 /CN−OH for 2,4-dichlorophenol (2,4-DCP) degradation comes up to 6 times of bare CeO 2 or g−C 3 N 4 . Compared to conventional CeO 2 /g−C 3 N 4 , the CeO 2 /CN−OH showed 65.9 % and 23.2 % improvement for 2,4-DCP and Cr(VI) removal, respectively. The significantly enhanced photodegradation ascribe to the alkaline modified CN−OH and the fabrication of CeO 2 /CN−OH n–n type heterojunction, both can improve the charge separation efficiency and increase the reaction active sites. Furthermore, the probable pathway and concreted photocatalytic mechanism for 2,4-DCP degradation are proposed based on the detected intermediate products.