scholarly journals Preparation and Photocatalytic Properties of N-Doped Graphene/TiO2 Composites

2020 ◽  
Vol 2020 ◽  
pp. 1-10
Author(s):  
Jing Liu ◽  
Kun-Yu Chen ◽  
Jie Wang ◽  
Min Du ◽  
Zheng-Yang Gao ◽  
...  
Keyword(s):  
Photocatalytic Activity ◽  
Adsorption Capacity ◽  
Ultraviolet Light ◽  
Diffuse Reflectance Spectroscopy ◽  
Photogenerated Electron ◽  
Light Irradiation ◽  
Electron Hole ◽  
X Ray ◽  
Ultraviolet Light Irradiation ◽  
Doped Graphene

N-doped graphene (NG)/TiO2 composites were prepared by a two-step hydrothermal method using HF as the surface etchant and urea as the nitrogen source. The morphology, structure, and bonding conditions of the NG/TiO2 composites were characterized by X-ray diffraction (XRD), field emission scanning electron microscopy (FESEM), X-ray photoelectron spectroscopy (XPS), Raman spectroscopy, UV-visible diffuse reflectance spectroscopy (UV-Vis DRS), and photoluminescence (PL) spectroscopy. The effects of NG on the lifetime of photogenerated electron-hole pairs, adsorption capacity, and photocatalytic activity of the composite photocatalysts were also investigated. The photocatalytic activity was evaluated under ultraviolet light and sunlight irradiation. The recovery testing was completed under ultraviolet light irradiation. The results show that TiO2 was uniformly loaded on the NG surface by chemical bonding. The introduction of NG effectively inhibited the recombination of photogenerated electron-hole pairs and improved both the adsorption capacity and photocatalytic activity of the composites. The 7 wt % NG/TiO2 showed the best adsorption capacity of methyl orange (MO). The best photocatalytic activity occurred for 5 wt % NG/TiO2 composites, and after four recovery tests, the photocatalytic degradation of MO under 60 min ultraviolet light irradiation exceeded 90%.

scholarly journals Synthesis and photocatalytic activity of ZnO/CuO composite for the degradation of methyl blue under vilsible light iradiation

2020 ◽  
Vol 9 (3) ◽  
pp. 94-100
Author(s):  
Kim Nguyen Van ◽  
Nga Nguyen Thi Viet ◽  
Tuyen Vo Thi Thanh ◽  
Vien Vo
Keyword(s):  
Photocatalytic Activity ◽  
Diffuse Reflectance ◽  
Diffuse Reflectance Spectroscopy ◽  
Photogenerated Electron ◽  
Reflectance Spectroscopy ◽  
X Ray Diffraction ◽  
Electron Hole ◽  
X Ray ◽  
Microwave System ◽  
Direct Formation

Composite ZnO/CuO was prepared by direct formation of ZnO from Zn(OOCCH3)2 precursor in the presence of CuO with the assistant of the microwave system. The obtained composite was characterized by X-Ray Diffraction (XRD) and Ultraviolet–Visible Diffuse Reflectance Spectroscopy (UV-vis DRS), which shows that the composite with a bandgap of 3.27 eV contains two components, ZnO and CuO. The photocatalytic activity of ZnO/CuO was assessed by the degradation of methylene blue (MB) in water under visible light, shows that the photocatalytic activity for the ZnO/CuO composite was remarkably improved compared to single ZnO and CuO. This result is attributed to the reduced recombination rate of photogenerated electron-hole pairs by the presence of CuO in the composite, therefore photocatalysis activity increases.

scholarly journals Synthesis of WO3/Ag3VO4 photocatalyst applying for the treatment of amoxicillin antibiotics under visible light

2021 ◽  
Vol 63 (11) ◽  
pp. 75-79
Author(s):  
Thi Thu Phuong Tran ◽  
◽  
My Ngoc Tram Dinh ◽  
Thi Yen Nhi Pham ◽  
Vu Ngoc Mai Nguyen ◽  
...  
Keyword(s):  
Photocatalytic Activity ◽  
Visible Light ◽  
Adsorption Capacity ◽  
Visible Light Irradiation ◽  
Photogenerated Electron ◽  
Reflectance Spectra ◽  
Light Irradiation ◽  
Electron Hole ◽  
Efficient Separation ◽  
Highly Active

In this paper, WO3/Ag3VO4 photocatalysts were successfully synthesised at various Ag3VO4/WO3 mole ratiosof5, 10, 15, and 20%(WA-x). Ultraviolet-visiblediffuse reflectance spectra (UV-Vis-DRS) indicated that the adsorption capacity of WA-10 (10% Ag3VO4/WO3 mole ratios) under visible light was higher than that of other materials. The photocatalytic properties of obtained materials were investigated by degradation of the antibiotic AMX under visible light irradiation. The degradation conversation of AMX had gotten to about 79.86% in WA-10 after a reaction of three hours. WO3/Ag3VO4 materials were highly active than WO3 and Ag3VO4 with an increase in photocatalytic activity of WO3/Ag3VO4 that can be attributed to the efficient separation of photogenerated electron-hole pairs.

Photocatalytic Degradation of Methylene Blue over Co-Ag3VO4 under Visible Light Irradiation

2011 ◽  
Vol 335-336 ◽  
pp. 1385-1390 ◽  
Author(s):  
Shuo Wiei Zhao ◽  
Hui Xu ◽  
Hua Ming Li ◽  
Yuan Guo Xu
Keyword(s):  
Methylene Blue ◽  
Photocatalytic Activity ◽  
Visible Light ◽  
Visible Light Irradiation ◽  
Absorption Edge ◽  
Diffuse Reflectance Spectroscopy ◽  
Dye Degradation ◽  
Light Irradiation ◽  
Experimental Conditions ◽  
X Ray

In order to improve the photocatalytic activity, Co was successfully loaded into Ag3VO4 by using impregnation process. The samples were characterized by X-ray diffraction (XRD), scanning electron microscope (SEM), energy-dispersive X-ray spectroscopy (EDS) and diffuse reflectance spectroscopy (DRS). The XRD and SEM–EDS analyses revealed that Co ion was dispersed on Ag3VO4. The DRS results indicated that the absorption edge of the Co–Ag3VO4 catalyst shifted to longer wavelength. The enhanced photocatalytic activity of Co–Ag3VO4 for Methylene Blue(MB) dye degradation under visible light irradiation was due to its wider absorption edge and higher separation rate of photo-generated electron and holes. In the experimental conditions, it is demonstrated that the MB was effectively degraded by more than 95% within 40 min when the Co–Ag3VO4 catalyst was calcined at 300°C with 1 wt.% Co content.

Enhanced visible-active photocatalytic behaviors observed in Mn-doped BiFeO3

2018 ◽  
Vol 32 (17) ◽  
pp. 1850185 ◽  
Author(s):  
Yun-Hui Si ◽  
Yu Xia ◽  
Ya-Yun Li ◽  
Shao-Ke Shang ◽  
Xin-Bo Xiong ◽  
...  
Keyword(s):  
Photocatalytic Activity ◽  
Visible Light ◽  
Band Gap ◽  
Diffuse Reflectance Spectroscopy ◽  
X Ray Diffraction ◽  
Electron Hole ◽  
X Ray ◽  
Mn Doped ◽  
Hole Recombination ◽  
Narrow Band Gap Semiconductors

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.

Preparation of BiXY(2-X)O3 and its Photocatalytic Degradation of Molasses Fermentation Wastewater under Visible-Light Irradiation

2011 ◽  
Vol 287-290 ◽  
pp. 1640-1645 ◽  
Author(s):  
Min Guang Fan ◽  
Zu Zeng Qin ◽  
Zi Li Liu ◽  
Tong Ming Su
Keyword(s):  
Photocatalytic Activity ◽  
Visible Light ◽  
Photocatalytic Degradation ◽  
Visible Light Irradiation ◽  
Photoelectron Spectroscopy ◽  
Diffuse Reflectance ◽  
Diffuse Reflectance Spectroscopy ◽  
Active Oxygen Species ◽  
Light Irradiation ◽  
X Ray

A series of BixY(2-x)O3photocatalysts were successfully prepared by a solid-state reaction and were subsequently characterized by powder X-ray diffraction, UV-vis diffuse reflectance spectroscopy, and X-ray photoelectron spectroscopy (XPS). The UV-vis diffuse reflectance spectra revealed that the BixY(2-x)O3samples absorbed light in the visible-light range (400-800 nm). The XPS results indicated that active oxygen species were generated on the Bi1.8Y0.2O3surface, which displayed a higher photocatalytic activity. When using photocatalytic degradation molasses fermentation wastewater as a model reaction, the Bi1.8Y0.2O3showed higher photocatalytic activity in comparison to Bi0.2Y1.8O3under visible-light irradiation.

A simple method to synthesise Ag-doped TiO2 photocatalysts with different Ag0:Ag2O atomic ratios for enhancing visible-light photocatalytic activity

2017 ◽  
Vol 41 (8) ◽  
pp. 475-483 ◽  
Author(s):  
C. Chen ◽  
X. F. Lei ◽  
M. Z. Xue
Keyword(s):  
Electron Microscopy ◽  
Photocatalytic Activity ◽  
Visible Light ◽  
Visible Light Irradiation ◽  
Light Absorption ◽  
Separation Efficiency ◽  
Visible Region ◽  
Light Irradiation ◽  
Electron Hole ◽  
X Ray

Pure anatase TiO2 photocatalysts with different Ag contents were prepared via a simple sol-gel method. The as-prepared anatase Ag-doped TiO2 photocatalysts were characterised by X-ray diffraction, transmission electron microscopy, UV-Vis diffuse reflectance spectra, photoluminescence spectroscopy, X-ray photoelectron spectroscopy, thermal gravity and differential thermal analysis, scanning electron microscopy and N2 adsorption–desorption measurements (BET). Compared with pure TiO2, Ag-doped anatase TiO2 photocatalysts exhibited not only increases in light absorption in the visible region, the separation efficiency of electron–hole pairs and surface area, but also inhibition of the titania phase transition from anatase to rutile. Photoreduction results showed that Ag-doped anatase TiO2 photocatalysts have greatly improved photocatalytic activity, compared with pure TiO2, and the reduction of Cr(VI) under visible light irradiation was much higher than that of pure TiO2. The optimum Ag content was 1.0 mol%, which led to the complete reduction of Cr(VI) under visible light irradiation (λ > 420 nm) for 4 h. The enhanced photocatalytic activity was attributed to the synergic effect of the pure anatase structure, and the increased light absorption in the visible region, separation efficiency of electron–hole pairs and atomic ratio of Ag0:Ag2O.

Preparation of Magnetic Ni0.5Zn0.5Fe2O4/ZnO Nanocomposites and Their Photocatalytic Performances for Methylene Blue in Aqueous Solution

2020 ◽  
Vol 20 (12) ◽  
pp. 7506-7515
Author(s):  
Wei Huang ◽  
Qing-Mei Yu ◽  
Yan-Yan Wang ◽  
Yue-Yang Xu ◽  
Wei Zhou ◽  
...  
Keyword(s):  
Methylene Blue ◽  
Photocatalytic Activity ◽  
Photogenerated Electron ◽  
Diffuse Reflection Spectroscopy ◽  
X Ray Diffraction ◽  
Electron Hole ◽  
X Ray ◽  
Coprecipitation Process ◽  
Size Of Particles ◽  
The Fourier Transform

Magnetic Ni0.5Zn0.5Fe2O4/ZnO-R (NZFO/ZnO-R) nanocomposites are prepared via the rapid combustion-coprecipitation process, and they are characterized by the Fourier Transform Infrared Spectroscopy (FTIR), the X-ray Diffraction (XRD), the Scanning Electron Microscopy (SEM), the Energy Dispersive X-ray Detector (EDX), the Specific Surface Area (BET), the UV-vis Diffuse Reflection Spectroscopy (DRS), and the Vibrating Sample Magnetometer (VSM). The photocatalytic activity of NZFO/ZnO-R nanocomposites is assessed in ultraviolet light (365 nm) by decoloration of methylene blue (MB). The results show that the magnetic NZFO/ZnO-0.2 nanocomposites consist of particles and rods. The size of particles is 18 nm. The width and length of rods are 66 nm and 198 nm, respectively. NZFO/ZnO-0.5 nanocomposites have better photocatalytic performance than that of NZFO, ZnO and NZFO/ZnO-R (R = 0.2, 0.3, 0.4, 0.6, or 0.7) from the results. Through careful investigation of influencing parameters (the amount of catalysts, pH and concentration of MB solution), the degradation efficiency of MB is closely connected with the transparency of solution and surface charge of catalysts. The enhanced photocatalytic activity of NZFO/ZnO-0.5 nanocomposites can be ascribed to the matching band positions between ZnO and NZFO, which results in a low recombination between the photogenerated electron-hole pairs. The possible mechanism is proposed for the improved ultraviolet photocatalytic activity of NZFO/ZnO-0.5 nanocomposites.

scholarly journals Preparation, Characterization, and Photocatalytic Applications of MWCNTs/TiO2Composite

2014 ◽  
Vol 2014 ◽  
pp. 1-8 ◽  
Author(s):  
Ahmed M. Kamil ◽  
Falah H. Hussein ◽  
Ahmed F. Halbus ◽  
Detlef W. Bahnemann
Keyword(s):  
Photocatalytic Activity ◽  
Diffuse Reflectance ◽  
Diffuse Reflectance Spectroscopy ◽  
Multiwall Carbon Nanotubes ◽  
Photogenerated Electron ◽  
Drying Process ◽  
Electron Hole ◽  
Activity Performance ◽  
Photocatalytic Applications ◽  
Multiwall Carbon

The multiwall carbon nanotubes (MWCNTs)/titanium dioxide (P25) composite in different ratios was prepared using simple evaporation and drying process. The composite was characterized by Raman spectroscopy, X-ray diffraction (XRD), UV-visible diffuse reflectance spectroscopy, and scanning electron microscopy (SEM). The photocatalytic activity of this composite was investigated using degradation of the Bismarck brown R dye (BBR). An optimal MWCNTs/TiO2ratio of 0.5% (w/w) was found to achieve the maximum rate of BBR degradation. It was observed that the composite exhibits enhanced photocatalytic activity compared with TiO2. The enhancement in photocatalytic activity performance of the MWCNTs/P25 composite is explained in terms of recombination of photogenerated electron-hole pairs. In addition, MWCNTs act as a dispersing support to control the morphology of TiO2particles in the MWCNTs/TiO2composite.

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