scholarly journals Magnetically Recoverable TiO2/SiO2/γ-Fe2O3/rGO Composite with Significantly Enhanced UV-Visible Light Photocatalytic Activity

Molecules ◽  
2020 ◽  
Vol 25 (13) ◽  
pp. 2996 ◽  
Author(s):  
Reyhaneh Kaveh ◽  
Maryam Mokhtarifar ◽  
Mojtaba Bagherzadeh ◽  
Andrea Lucotti ◽  
Maria Vittoria Diamanti ◽  
...  

In this paper, we report the preparation of a new composite (TiO2/SiO2/γ-Fe2O3/rGO) with a high photocatalytic efficiency. The properties of the composite were examined by different analyses, including X-ray diffraction (XRD), field emission scanning electron microscope (FE-SEM), photoluminescence (PL), UV-Visible light diffuse reflectance spectroscopy, Fourier transform infrared spectroscopy (FTIR), Raman, vibrating-sample magnetometer (VSM), and nitrogen gas physisorption (BET) studies. The photocatalytic efficiency of the proposed composite was evaluated by the degradation of methylene blue under UV and visible light, and the results were compared with titanium dioxide (TiO2), where degradation increased from 30% to 84% and 4% to 66% under UV and visible light, respectively. The significant increase in photocatalytic activity may be explained by the higher adsorption of dye on the surface of the composite and the higher separation and transfer of charge carriers, which in turn promote active sites and photocatalytic efficiency.

2011 ◽  
Vol 117-119 ◽  
pp. 803-806
Author(s):  
Pei Song Tang ◽  
Hai Feng Chen ◽  
Feng Cao ◽  
Guo Xiang Pan ◽  
Min Hong Xu

The Nano-Bi2MoO6was prepared using Bi(NO3)3•5H2O and Na2MoO4•2H2O as starting materials by a hydrothermal process. The prepared Bi2MoO6product was characterized by powder X-ray diffraction (XRD), scanning electron microscopy (SEM) and UV-visible diffuse reflectance spectroscopy (DRS). It was found that the prepared nano-Bi2MoO6show narrow band gap of 2.88 eV. Consequently, the prepared nano-Bi2MoO6show high visible-light photocatalytic activity for decomposition of Rhodamine B in comparison with the commercial Degussa P25, which was ascribed to the visible-light absorption.


2014 ◽  
Vol 809-810 ◽  
pp. 140-143 ◽  
Author(s):  
Chao Wan Tang ◽  
Jia Ni Ying ◽  
Dong Jing Ni ◽  
Qian Yang ◽  
Li Mei Wu ◽  
...  

Using Er (NO3)3·5H2O and Fe (NO3)3·9H2O as major materials, the ErFeO3 nanoparticles were prepared by successive microwave processing and high temperature calcination. The samples were characterized by thermogravimetric and differential thermal analysis (TG-DTA), powder X-ray diffraction (XRD), scanning electron microscopy (SEM) and UV-visible diffuse reflectance spectroscopy (DRS). It was found that the single phase ErFeO3 can be obtained through the calcination of microwave processed ErFeO3 precursors at 800°C, and the resulting product was approximation flake of 20-80 nm. The visible-light photocatalytic activity of ErFeO3 nanoparticles was investigated in experimental simulation wastewater containing 10 mg/L methyl orange (MO). The results show that ErFeO3 nanoparticles appear high photocatalytic activity for the decomposition of MO under visible-light irradiation.


2018 ◽  
Vol 32 (17) ◽  
pp. 1850185 ◽  
Author(s):  
Yun-Hui Si ◽  
Yu Xia ◽  
Ya-Yun Li ◽  
Shao-Ke Shang ◽  
Xin-Bo Xiong ◽  
...  

A series of BiFeO3 and BiFe[Formula: see text]Mn[Formula: see text]O3 (x = 0, 0.02, 0.04, 0.06, 0.08, 0.10) were synthesized by a hydrothermal method. The samples were characterized by X-ray diffraction, scanning electron microscopy, energy dispersive spectroscopy (EDS) and UV–Vis diffuse reflectance spectroscopy, and their photocatalytic activity was studied by photocatalytic degradation of methylene blue in aqueous solution under visible light irradiation. The band gap of BiFeO3 was significantly decreased from 2.26 eV to 1.90 eV with the doping of Mn. Furthermore, the 6% Mn-doped BiFeO3 photocatalyst exhibited the best activity with a degradation rate of 94% after irradiation for 100 min. The enhanced photocatalytic activity with Mn doping could be attributed to the enhanced optical absorption, increment of surface reactive sites and reduction of electron–hole recombination. Our results may be conducive to design more efficient photocatalysts responsive to visible light among narrow band gap semiconductors.


2014 ◽  
Vol 809-810 ◽  
pp. 890-894
Author(s):  
Dan Li ◽  
Lian Wei Shan ◽  
Gui Lin Wang ◽  
Li Min Dong ◽  
Wei Li ◽  
...  

Boron-BiVO4 samples were synthesized by sol-gel method. They were characterized by UV-vis diffuse reflectance spectroscopy, X-ray diffraction. Photocatalytic activity of the obtained BiVO4 samples was investigated through degrading methylene blue (MB). The results reveal that boron-BiVO4 catalysts have monoclinic scheelite structure. The BiVO4 and Co-BiVO4 photocatalysts were responsive to visible light. Co-BiVO4 photocatalyst showed higher photocatalytic activity than pure BiVO4, resulting in the significantly improved efficiency of degradation of MB.


2014 ◽  
Vol 787 ◽  
pp. 35-40 ◽  
Author(s):  
Xiao Yan Zhou ◽  
Peng Wei Zhou ◽  
Hao Guo ◽  
Bo Yang ◽  
Ru Fei Ren

The p-n junction photocatalysts, p-CuO (at. 0-25%)/n-ZnO nanocomposite were prepared through hydrothermal method without using any organic solvent or surfactant. The as-prepared samples were characterized by X-ray diffraction, scanning electron microscopy, energy dispersive X-Ray spectroscopy, and UV-vis spectroscopy. The results demonstrated that the CuO/ZnO nanocomposite presented a two-dimensional morphology composed of sheet-like ZnO nanostructures adorned with CuO nanoparticles. The photocatalytic activity of CuO/ZnO with different Cu/Zn molar rations and pure ZnO synthesized by the identical synthetic route were evaluated by degrading methylene blue (MB) dye under UV-visible light irradiation. The CuO/ZnO with Cu/Zn molar ratio of 4% exhibits the highest photocatalytic activity compared that of the other photocatalysts under the identical conditions. It is mainly attributed to the increased charge separation rate in the nanocomposite and the extended photo-responding range.


2014 ◽  
Vol 636 ◽  
pp. 7-10 ◽  
Author(s):  
Pei Song Tang ◽  
Chao Wan Tang ◽  
Jia Ni Ying ◽  
Dong Jing Ni ◽  
Qian Yang ◽  
...  

Using Fe (NO3)3⋅9H2O, Y(NO3)3⋅6H2O and citric acid as the main raw material, the YFeO3 nanoparticles were synthesized by ultrasonic assisted process and calcination. The YFeO3 nanoparticles were characterized by thermogravimetry and differential thermal analysis (TG-DTA), powder X-ray diffraction (XRD), scanning electron microscopy (SEM) and UV-visible diffuse reflectance spectroscopy (DRS). The results show that the perovskite structureYFeO3 (YFeO3-800) can be obtained through the calcination of ultrasonic processed YFeO3 precursors at 800 °C, and the resulting product has a particle size of 70 nm and an optical band gap of 2.0 eV. Consequently, the YFeO3-800 nanoparticles show high photocatalytic activity for decomposition of methyl orange under visible-light irradiation.


2012 ◽  
Vol 621 ◽  
pp. 172-177 ◽  
Author(s):  
Su Hua Chen ◽  
Bi Xuan Wang ◽  
Xian Hua Qiu ◽  
Zhen Sheng Xiong

In order to improve ZnWO4 photocatalytic activity under visible light, the C, N-codoped ZnWO4 nanoparticles have been successfully synthesized by choosing C3N4 generated from tripolycyanamide pyrolysis as the source of Carbon and Nitrogen and the influence of C3N4 concentration on structural, optical and morphological properties of C, N-codoped ZnWO4 using X-ray diffraction (XRD), UV-visible spectroscopy, scanning electron microscopy (SEM) and photocatalytic decoloration of rhodamine B (RhB) aqueous solution under visible light. It was found that the presence of carbon and nitrogen could not improve the crystallization of ZnWO4 species but could enhance their photoabsorption property in the visible region. The results also showed that the photocatalytic activity of the as-prepared ZnWO4 is higher than that of pure ZnWO4 with the optimum effect occurring at RC3N4 = 9 % (the weight ratio of tripolycyanamide to ZnWO4)


2015 ◽  
Vol 2015 ◽  
pp. 1-8 ◽  
Author(s):  
Qianzhi Xu ◽  
Xiuying Wang ◽  
Xiaoli Dong ◽  
Chun Ma ◽  
Xiufang Zhang ◽  
...  

S/Zn codoped TiO2nanomaterials were synthesized by a sol-gel method. X-ray diffraction, UV-vis diffuse reflectance spectroscopy, transmission electron microscopy, photoluminescence spectroscopy, and X-ray photoelectron spectroscopy were used to characterize the morphology, structure, and optical properties of the prepared samples. The introduction of Zn and S resulted in significant red shift of absorption edge for TiO2-based nanomaterials. The photocatalytic activity was evaluated by degrading reactive brilliant red X-3B solution under simulated sunlight irradiation. The results showed S/Zn codoped TiO2exhibited higher photocatalytic activity than pure TiO2and commercial P25, due to the photosynergistic effect of obvious visible light absorption, efficient separation of photoinduced charge carriers, and large surface area. Moreover, the content of Zn and S in the composites played important roles in photocatalytic activity of TiO2-based nanomaterials.


2013 ◽  
Vol 631-632 ◽  
pp. 399-403
Author(s):  
Xi Ming Luo ◽  
Fen Fen Li ◽  
Hong Tao Gao

Sm, Zr doped nanocrystalline TiO2 powers were prepared successfully by a facile ultrasonic assisted sol-gel method. The products were characterized by X-ray diffraction (XRD) and scanning electron microscope (SEM), respectively. X-ray diffraction peaks could be assigned to anatase TiO2, which confirms the crystallinity of the as-prepared samples. The SEM images demonstrated that the crystalinity is formed with spherical aggregates with average diameters ranging from 10 to 20 nm. The photocatalytic activity was studied on the photocatalytic degradation of methyl orange (MO) aqueous solution irradiated with UV-visible light. Under UV-visible light irradiation, the photocatalytic performances of the doped samples were much better than that of pure TiO2, and the co-dopant showed highest. It demonstrated that a strong Sm-Zr synergistic interaction might play a decisive role in driving the excellent photocatalytic performance of TiO2.


2015 ◽  
Vol 1123 ◽  
pp. 227-232 ◽  
Author(s):  
Iqriah Kalim Susanto ◽  
Ardiansyah Taufik ◽  
Rosari Saleh

Nanocomposite Fe3O4-CuO-ZnO with different molar ratio of Fe3O4:CuO:ZnO were synthesized using sol-gel method and characterized by X-ray diffraction, energy dispersive X-ray spectroscopy, field emission scanning electron microscope, UV-visible diffuse reflectance spectroscopy and vibrating sample magnetometer. The characterization results manifested that the combination of Fe3O4, CuO and ZnO nanoparticles was successful. The photocatalytic activity of nanocomposite with the molar ratio of 1:1:5 was more effective in the degradation of methylene blue under UV light irradiation than pure Fe3O4, CuO, ZnO. The role of photoactive species involved in the photocatalytic reaction was studied and found that holes play the most important role in photodegradation of methylene blue.


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