scholarly journals Annealing Effect of ZnO Seed Layer on Enhancing Photocatalytic Activity of ZnO/TiO2Nanostructure

2013 ◽  
Vol 2013 ◽  
pp. 1-7 ◽  
Author(s):  
Woo-Young Kim ◽  
Soon-Wook Kim ◽  
Dae-Hwang Yoo ◽  
Eui Jung Kim ◽  
Sung Hong Hahn
Keyword(s):  
Photocatalytic Activity ◽  
Seed Layer ◽  
Zno Nanorods ◽  
X Ray Diffraction ◽  
Flower Structure ◽  
Electron Recombination ◽  
Electron Hole ◽  
Oxygen Defects ◽  
Uv Visible ◽  
Beam Deposition

Zinc oxide (ZnO)/titanium dioxide (TiO2) nanorods have been synthesized via a hydrothermal method for ZnO nanorods and an electron-beam deposition for TiO2nanorods. This work examined the effect of annealing ZnO seed layer on the photocatalytic activity of the ZnO/TiO2nanorods which was determined from photodecomposition of methylene blue under UV irradiation. The photocatalytic activity of the ZnO/TiO2nanorods was improved with increasing annealing temperature of the seed layer from 300°C to 500°C. Annealing the seed layer at 500°C showed the best photocatalytic activity resulting from high UV absorption ability, a large surface area with flower structure and copious oxygen defects which promote separation of electron-hole pairs reducing electron recombination. The prepared nanorods were characterized by field emission-scanning electron microscopy (FE-SEM), X-ray diffraction (XRD), photoluminescence (PL), and UV-visible spectroscopy.

Enhanced photocatalytic activity of Ag-coated ZnO nanorods for the degradation of methylene blue

2020 ◽  
Vol 0 (0) ◽  
Author(s):  
Riaz Ahmad ◽  
Sami Ul Haq ◽  
Sohail Muhammad ◽  
Gulzar Khan ◽  
Said Karim Shah ◽  
...  
Keyword(s):  
Methylene Blue ◽  
Photocatalytic Activity ◽  
Zno Nanorods ◽  
Visible Range ◽  
Human Beings ◽  
X Ray Diffraction ◽  
Ag Nps ◽  
Aquatic Life ◽  
One Step ◽  
Uv Visible

AbstractWorldwide water pollution is a serious issue, which needs special attention. Among these pollutants, methylene blue (MB) is dangerous for aquatic life as well as for human beings. Researchers are trying their best to degrade the various pollutants found in water. In the present work, we synthesized ZnO nanorods (NRDs) by one-step hydrothermal method. The synthesized samples were then characterized with the help of X-ray Diffraction (XRD) and Scanning Electron Microscopy (SEM). ZnO nanostructures were composed of rod-shaped NRDs with flat edges and were highly crystalline with hexagonal shaped morphology. UV/Visible spectroscopy was carried out to investigate the optical properties, which shows the absorption in UV range and highly transmittance in the visible range. Finally, the photocatalytic activity was performed for the degradation of MB. The results show that MB was not fully degraded by bare ZnO NRDs. After all, we coated Ag NPs on the surfaces of ZnO NRDs through the simple solution-based method. The UV/Visible data reveal absorption in the UV as well as in the visible range due to the surface plasmonic effect of Ag NPs. Hybrid Ag-coated ZnO NRDs successfully degraded MB within 60 min. Therefore, we found that Ag-coated ZnO NRDs show good photocatalytic properties as compared to uncoated ZnO NRDs.

Few-Layered MoS2 Nanostructures for Highly Efficient Visible Light Photocatalysis

NANO ◽  
2016 ◽  
Vol 11 (10) ◽  
pp. 1650114 ◽  
Author(s):  
Dan Li ◽  
Jianwei Li ◽  
Caiqin Han ◽  
Xinsheng Zhao ◽  
Haipeng Chu ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Photocatalytic Activity ◽  
Visible Light ◽  
Electrochemical Impedance ◽  
X Ray Diffraction ◽  
Electron Hole ◽  
Electrochemical Impedance Spectra ◽  
X Ray ◽  
Transmission Electron ◽  
Electron Hole Pair

Few-layered MoS2 nanostructures were successfully synthesized by a simple hydrothermal method without the addition of any catalysts or surfactants. Their morphology, structure and photocatalytic activity were characterized by X-ray diffraction, scanning electron microscopy, energy dispersive X-ray spectroscopy, transmission electron microscopy, electrochemical impedance spectra and UV-Vis absorption spectroscopy, respectively. These results show that the MoS2 nanostructures synthesized at 180[Formula: see text]C exhibit an optimal visible light photocatalytic activity (99%) in the degradation of Rhodamine B owing to the relatively easier adsorption of pollutants, higher visible light absorption and lower electron–hole pair recombination.

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.

scholarly journals Decolorization of Methylene Blue by Ag/SrSnO3 Composites under Ultraviolet Radiation

2014 ◽  
Vol 2014 ◽  
pp. 1-10 ◽  
Author(s):  
Patcharanan Junploy ◽  
Titipun Thongtem ◽  
Somchai Thongtem ◽  
Anukorn Phuruangrat
Keyword(s):  
Electron Microscopy ◽  
Methylene Blue ◽  
Uv Radiation ◽  
Photoelectron Spectroscopy ◽  
Separation Process ◽  
X Ray Diffraction ◽  
Electron Hole ◽  
X Ray ◽  
Negative Effect ◽  
Uv Visible

SrSn(OH)6 precursors synthesized by a cyclic microwave radiation (CMR) process were calcined at 900°C for 3 h to form rod-like SrSnO3. Further, the rod-like SrSnO3 and AgNO3 in ethylene glycol (EG) were ultrasonically vibrated to form rod-like Ag/SrSnO3 composites, characterized by X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), electron microscopy (EM), Fourier transform infrared (FTIR) spectroscopy, and UV-visible analysis. The photocatalyses of rod-like SrSnO3, 1 wt%, 5 wt%, and 10 wt% Ag/SrSnO3 composites were studied for degradation of methylene blue (MB, C16H18N3SCl) dye under ultraviolet (UV) radiation. In this research, the 5 wt% Ag/SrSnO3 composites showed the highest activity, enhanced by the electron-hole separation process. The photoactivity became lower by the excessive Ag nanoparticles due to the negative effect caused by reduction in the absorption of UV radiation.

Hierarchical growth of ZnO nanorods over SnO2 seed layer: insights into electronic properties from photocatalytic activity

RSC Advances ◽  
2016 ◽  
Vol 6 (3) ◽  
pp. 2112-2118 ◽  
Author(s):  
Luís F. Da Silva ◽  
Osmando F. Lopes ◽  
Ariadne C. Catto ◽  
Waldir Avansi ◽  
Maria I. B. Bernardi ◽  
...  
Keyword(s):  
Photocatalytic Activity ◽  
Electronic Properties ◽  
Hydrothermal Treatment ◽  
Charge Separation ◽  
Seed Layer ◽  
Photocatalytic Performance ◽  
Zno Nanorods

The ZnO–SnO2 heterojunction catalyst was prepared via a hydrothermal treatment route. The heterojunction exhibited a superior photocatalytic performance in comparison to SnO2 and ZnO, attributed to the good charge separation.

Hierarchical Nanostructured ZnO-CuO Nanocomposite and its Photocatalytic Activity

2015 ◽  
Vol 35 ◽  
pp. 21-26 ◽  
Author(s):  
Susmita Das ◽  
Vimal Chandra Srivastava
Keyword(s):  
Photocatalytic Activity ◽  
Pure Copper ◽  
Ultra Violet ◽  
Xrd Analysis ◽  
Sem Analysis ◽  
X Ray Diffraction ◽  
X Ray ◽  
Ultra Violet Radiation ◽  
One Step ◽  
Uv Visible

Metal oxide nanocomposite (ZnO-CuO) was successfully synthesized by one step homogeneous coprecipitation method and further characterized by Fourier transform infrared spectroscopy (FTIR), scanning electron micrograph (SEM), X-ray diffraction analysis (XRD) and UV-visible diffuse reflectance spectra. XRD analysis exhibited presence of pure copper oxide and zinc oxide within the nanocomposite. SEM analysis indicated that the ZnO-CuO nanocomposite was consisted of flower shaped ZnO along with leaf shaped CuO. Photocatalytic activity of nanocomposite was evaluated in terms of degradation of methylene blue (MB) dye solution under ultra-violet radiation. Results showed that the photocatalytic efficiency of ZnO-CuO nanocomposite was higher than its individual pure oxides (ZnO or CuO).

Influence of Ag Doping on the Crystal Structure and Photocatalytic Activity of FeVO4

2011 ◽  
Vol 197-198 ◽  
pp. 919-925 ◽  
Author(s):  
Min Wang ◽  
Qiong Liu
Keyword(s):  
Photocatalytic Activity ◽  
Methyl Orange ◽  
Photoelectron Spectroscopy ◽  
Methyl Orange Solution ◽  
Precipitation Method ◽  
X Ray Diffraction ◽  
Electron Hole ◽  
X Ray ◽  
Orange Solution ◽  
Decoloration Rate

Silver (Ag+) doped iron (III) vanadate (FeVO4) samples are prepared by the precipitation method and then characterized by X-ray diffraction (XRD), scanning electron microscope (SEM), and X-ray photoelectron spectroscopy(XPS). The photocatalytic activity under visible light is evaluated by photocatalytic degradation of methyl orange (MO) in the solution. The results show that both FeVO4 and Ag+ doped FeVO4 samples are triclinic, the later have different surface morphology, and some needle-shaped materials appear in the later. From XPS, there are more Fe2+ ions in Ag+ doped FeVO4 sample than that in FeVO4 one without Ag+. It indicates that Ag+ doping can increase the density of the surface oxygen vacancies of catalysts, which can act as electron traps promoting the electron-hole separation and then increase the photo-activity. The decoloration rate after Ag+ doping against methyl orange solution can reach about 81%, and be more about 20％ than that of pure FeVO4.

Photocatalytic Activity of CuO/ZnO Heterostructure Nanocrystals under UV-Visible Light Irradiation

2014 ◽  
Vol 787 ◽  
pp. 35-40 ◽  
Author(s):  
Xiao Yan Zhou ◽  
Peng Wei Zhou ◽  
Hao Guo ◽  
Bo Yang ◽  
Ru Fei Ren
Keyword(s):  
Photocatalytic Activity ◽  
Visible Light ◽  
Visible Light Irradiation ◽  
Cuo Nanoparticles ◽  
Light Irradiation ◽  
Molar Ratio ◽  
X Ray Diffraction ◽  
X Ray ◽  
Vis Spectroscopy ◽  
Uv Visible

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.

PERFORMANCE OF pH SENSOR ELECTRODE BASED ON ZnO NRs ON FTO-GLASS SUBSTRATE

2020 ◽  
Vol 27 (08) ◽  
pp. 1950198
Author(s):  
ABDULQADER D. FAISAL ◽  
MOHAMMAD O. DAWOOD ◽  
HASSAN H. HUSSEIN ◽  
KHALEEL I. HASSOON
Keyword(s):  
Seed Layer ◽  
Zno Nanorods ◽  
Ph Sensor ◽  
High Sensitivity ◽  
Hydrothermal Growth ◽  
X Ray Diffraction ◽  
X Ray ◽  
Zno Nanocrystals ◽  
Electrode Cell ◽  
Fto Glass

In this work, ZnO nanorods (ZnO NRs) were successfully synthesized on FTO-glass via hydrothermal technique. Two steps were followed to grow ZnO NRs. In the first step, the seed layer of ZnO nanocrystals was deposited by using a drop cast method. The second step was represented by the hydrothermal growth of ZnO NRs on a pre-coated FTO- glass with the seed layer. The hydrothermal growth was conducted at 90∘C for 2[Formula: see text]h. The resulted structure, morphology and optical properties of the produced layers were analyzed by X-ray diffraction (XRD), field emission scanning electron microscope (FESEM) equipped with energy dispersive X-ray (EDX) and UV-visible spectrophotometer, respectively. The analysis confirmed that the ZnO NRs grown by the hydrothermal method have a hexagonal crystal structure which was grown randomly on the FTO surface. The crystallite size was recorded 50[Formula: see text]nm and a slight microstrain (0.142%) was calculated. The bandgap was found to be in the range of 3.14–3.17[Formula: see text]eV. The ZnO NRs have a high density and large aspect ratio. A pH sensor with high sensitivity was fabricated using a two-electrode cell configuration. The ZnO NRs sensor showed the sensitivity of [Formula: see text]59.03[Formula: see text]mV/pH, which is quite promising and close to the theoretical value ([Formula: see text]59.12[Formula: see text]mV/pH).

Photocatalytic activity of SnO2–α-Fe2O3 composite mixtures: exploration of number of active sites, turnover number and turnover frequency

2018 ◽  
Vol 2 (4) ◽  
pp. 796-806 ◽  
Author(s):  
L. Gomathi Devi ◽  
R. Shyamala
Keyword(s):  
Photocatalytic Activity ◽  
Charge Transfer ◽  
Active Sites ◽  
Separation Process ◽  
Schematic Diagram ◽  
Charge Transfer Process ◽  
Turnover Frequency ◽  
Turnover Number ◽  
Electron Hole ◽  
Uv Visible

Schematic diagram showing energy band edge positions, vectorial charge transfer process and electron hole separation process in the SnO2–α-Fe2O3 composite under UV/visible light irradiation.

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