Ceria dioxide supported on graphitic carbon nitride (CeO 2 /g-C 3 N 4 ) composites were facilely synthesized to be application for photocatalytic hydrogen (H 2 ) generation in this present work. The physical and chemical properties of CeO 2 /g-C 3 N 4 nanocomposites were determined via a series of characterizations. The CeO 2 /g-C 3 N 4 composites prepared by facile thermal annealing and rotation-evaporation method exhibit excellent photocatalytic H 2 evolution with visible-light illumination. The best hydrogen generation rate of CeO 2 /g-C 3 N 4 composite with 1.5 wt% Pt is 0.83 mmol h −1 g −1 , which is almost same as that of composite with 3 wt% Pt prepared by simple physical mixing method. The significantly developed photocatalytic activity of CeO 2 /g-C 3 N 4 composite is majorly ascribed to the stronger interfacial effects with the more visible-light absorbance and faster electron transfer . This work reveals that construction of the CeO 2 /g-C 3 N 4 composite with high disperse and close knit by the facile thermal annealing and rotation-evaporation method could be an effective method to achieve excellent photocatalytic hydrogen evolution performance.
Dimensional regulation and heterostructure building strategy are the significant means to boost the property of semiconductor photocatalysts . Herein, CeO 2 /g-C 3 N 4 (CeCN) composites with 1D/3D structure were synthesized by compounding one-dimensional CeO 2 nanorods and three-dimensional porous carbon nitride materials. Diverse characterization methods, BET, XRD , SEM/TEM, FT-IR, XPS and UV–vis DRS , to name a few, were conducted to reveal the surface area, micro shape, crystal structure, surface functional groups and photoconductive properties of the samples. The photocatalytic properties of catalyst were estimated by photodegradation of ciprofloxacin (CIP) under visible light irradiation. The results suggested that CeO 2 nanorods with 1D structure and g-C 3 N 4 with 3D porous structure are successfully composite into 1D/3D composites without any crystal structure and surface functional groups changed. The optimal CeCN25 exhibited brilliant photodegradation performance with 96.3% degradation efficiency within 100 min under visible light irradiation. The dimension control strategy made the material form porous structure and increases the adsorption performance of the material, while the heterostructure construction strategy formed a space electric field with efficient charge separation and transfer, which prolonged charge life. The combination of two strategies was the crucial factor for the eminent catalytic activity of photocatalysts. This work supplies thinking for the directional design and synthesis of composite catalysts with high photocatalytic activity .
Lei Guo,Jingxia Yang,Huiqing Zhang,Runkai Wang,Jingli Xu,Jinjie Wang
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.
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