Qing Cen,Qiaoyuan Gao,Chenlu Zhang,Yingqi Liu,Qi Wang,Qi Wang
In this study, visible-light-active iron tungstosilicate (FeSiW) was fabricated via solvothermal method . Fe 3+ was applied as counter ion to precipitate with silicotungstic acid (H 4 SiW 12 O 40 ) in methanol solution. It can be observed from FT-IR spectra that the Keggin structure of SiW 12 O 40 4− was well maintained in FeSiW. Besides, the effect of different initial molar ratios of Fe 3+ to H 4 SiW 12 O 40 was investigated (from 4:1 to 4:4). By photoelectrochemical characterizations, such as photocurrent response and Mott-Schottky (M-S) plots, easiest generation of electron-hole pairs and lowest charge transfer resistance can be observed on FeSiW with initial molar ratio of 4:3. Moreover, FeSiW with 4:3 ratio also displayed highest activity for photocatalytic reduction of Cr(VI), despite of the largest band gap (ca. 2.71 eV). The lowest unoccupied molecular orbital (LUMO) and highest occupied molecular orbital (HOMO) of the optimized FeSiW were estimated to be +0.03 V and 2.74 V vs NHE, respectively, which were thermodynamically feasible for Cr(VI) reduction and H 2 O oxidation . Even under acidic condition (pH 3), the optimized photocatalyst displayed good stability in cyclic runs. Therefore, the present study opens a new way for heterogeneous polyoxometalates as efficient photocatalyst for environmental application.
Bin Xu,Tao Ding,Yongcai Zhang,Yaoting Wen,Zhanjun Yang,Ming Zhang
This communication reports the development of a new efficient visible-light-driven composite photocatalyst comprising ZnFe 2 O 4 nanoparticles and conjugated polymer (CPVC) from the dehydrochlorination of polyvinyl chloride (PVC). ZnFe 2 O 4 /CPVC nanocomposites were synthesized via three main steps: (i) the synthesis of ZnFe 2 O 4 nanoparticles by a sol-gel method; (ii) the adsorption of PVC in tetrahydrofuran solution by ZnFe 2 O 4 nanoparticles to form ZnFe 2 O 4 /PVC nanocomposites; and (iii) the dehydrochlorination of PVC in the ZnFe 2 O 4 /PVC nanocomposites by heating at 150 °C for 2 h. X-ray diffraction, Fourier transform infrared spectroscopy and high-resolution transmission electron microscopy characterization revealed that the as-synthesized product was core/shell structured ZnFe 2 O 4 /CPVC nanocomposites. The photocatalytic results demonstrated that the ZnFe 2 O 4 /CPVC nanocomposites had much higher photocatalytic activity than ZnFe 2 O 4 nanoparticles in the reduction of aqueous Cr(VI) under visible-light (λ>420 nm) irradiation. Thus, ZnFe 2 O 4 /CPVC nanocomposites are promising for use as a new efficient visible-light-driven photocatalyst .
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