ABSTRACT
Inspired by natural photosynthesis, artificial heterojunction photocatalysts have been extensively studied. Herein, a novel ternary graphitic carbon nitride/platinum/bismuth vanadate (g-C3N4/Pt/BiVO4) photocatalytic system was successfully synthesized, where Pt/BiVO4 nanosheet is anchored on the surface of layered g-C3N4, as evidenced by structural observations. Ultraviolet photoelectron spectroscopy and ultraviolet-visible diffuse reflectance spectroscopy are carried out to identify the position of the conduction band and valence band. A Z-scheme is used to interpret the superior photocatalytic performance of g-C3N4/Pt/BiVO4 and further verified by the capture of free radicals and terephthalic acid photoluminescence experiments. Compared with the g-C3N4/BiVO4 binary system, the Z-scheme g-C3N4/Pt/BiVO4 photocatalyst not only possesses enhanced carrier separation efficiency but also maintains sufficient redox properties, thus inducing superior photocatalytic activity. More importantly, the novel Z-scheme photocatalyst exhibits excellent recycle stability, which could provide inspiration for the rational design of efficient and practical photocatalysts for environmental pollution treatment. The ternary photocatalyst also exhibits significantly enhanced visible-light photocatalytic hydrogen production performance.
ABSTRACT
A series of novel Bi2MoO6/zeolitic imidazolate framework-8 (ZIF-8) photocatalysts have been successfully fabricated through a facile self-assembly process. X-ray diffraction (XRD), scanning electron microscopy (SEM), UV-vis spectrophotometry, and X-ray photoelectron spectroscopy (XPS) characterized pure Bi2MoO6, pure ZIF-8, and a series of Bi2MoO6/ZIF-8 composites. The result indicated that, when compared with pure Bi2MoO6, the composite of Bi2MoO6/ZIF-8 exhibited excellent photocatalytic performance for the degradation of methylene blue (MB) under visible light. Moreover, the Bi2MoO6/ZIF-8-3 composite (the molar ratio of Bi2MoO6 to 2-MI is 3:3) has optimum photocatalytic performance because of the suitable amount of ZIF-8 decorated on the flower-like Bi2MoO6. The enhanced photocatalytic activity is probably due to the introduction of ZIF-8, which will promote the separation of electron-hole pair and the surface morphology. Benefitting from the diversity of the MOF species (ZIF-8 is one of them), this composing strategy of Bi2MoO6/MOF composite would provide new insight into the design of highly efficient visible light photocatalysts.
ABSTRACT
BiFeO3/Reduced Graphene Oxide (BFO/RGO) composites have been fabricated by a simple hydrothermal method. The X-ray diffraction (XRD), scanning electron microscopy (SEM), Raman, and X-ray photoelectron spectroscopy (XPS) analysis reveal that graphene oxide was reduced in hydrothermal process and BFO/RGO composites were successfully synthesized. UV-visible absorption and photoluminescence properties show that the introduction of RGO can effectively reduce the recombination of photogenerated electron and hole pairs. Compared to the pristine BFO, the photocatalytic performance of BiFeO3 Graphene Oxide (BGO) composites is enhanced for the degradation of Methylene blue (MB) solution under visible light irradiation, and the result shows that the optimal amount of Graphene Oxide (GO) in the composites is 60 mg (BGO60). The excellent photocatalytic performance is mainly ascribed to improved light absorption, increased reactive sites, and the low recombination rate of electron-hole pairs. This work can provide more insights into designing advanced photocatalysts for wastewater treatment and environmental protection.