Structure and Photocatalytic Activity of Nitrogen-doped HTiNbO5 Nanosheet Aggregation

NANO ◽  
2017 ◽  
Vol 12 (01) ◽  
pp. 1750003 ◽  
Author(s):  
Wei Lv ◽  
Jie He ◽  
Andong Xu ◽  
Lifang Hu ◽  
Liangguo Da

Nitrogen-doped HTiNbO5 nanosheet (N-HTiNbO5-NS) aggregation was successfully obtained through a series of process, including preparation of nitrogen-doped precursor (N-KTiNbO5), proton-exchange of N-KTiNbO5 and exfoliation of N-HTiNbO5. The structures of the as-prepared samples are characterized by means of powder X-ray diffraction (XRD), Scan electron microscopy (SEM), Transmission electron microscopy (TEM), N2 adsorption-desorption isotherms UV-visible diffuse reflectance spectroscopy (UV-Vis-DRS), Laser Raman spectroscopy (LRS), X-ray photoelectron spectroscopy (XPS) and Thermogravimetric analysis-differential scanning calorimetry (TG-DSC). The catalytic activities of the as-prepared samples are evaluated by the photocatalytic degradation of methylene blue (MB) aqueous solution under visible light irradiation. The results reveal that N-HTiNbO5-NS due to the large specific surface area and brilliant visible light response exhibits a relatively excellent photocatalytic activity in the decomposition of MB under visible light irradiation.

2013 ◽  
Vol 2013 ◽  
pp. 1-7 ◽  
Author(s):  
Gang-Juan Lee ◽  
Chi-Lun Hong ◽  
Valentina Batalova ◽  
Gennady Mokrousov ◽  
Jerry Wu

Nitrogen modified zinc sulfide photocatalysts were successfully prepared and characterized by X-ray diffraction (XRD), field emission scanning electron microscopy (FE-SEM), high-resolution transmission electron microscopy (HR-TEM), X-ray photoelectron spectroscopy (XPS), and surface area analysis. Thermal decomposition of the semisolid was carried out under nitrogen conditions at 500°C for 2 hours, and a series of nitrogen-doped ZnS photocatalysts were produced by controlling inflow flow rate of nitrogen at 15–140 mL/min. Optical characterizations of the synthesized N-doping ZnS substantially show the shifted photoabsorption properties from ultraviolet (UV) region to visible light. The band gaps of nitrogen-doped ZnS composite catalysts were calculated to be in the range of 2.58~2.74 eV from the absorptions edge position. The 15N/ZnS catalyst shows the highest photocatalytic activity, which results in 75.7% degradation of Orange II dye in 5 hrs by visible light irradiation, compared with pristine ZnS and higher percentage N-doping ZnS photocatalysts.


2011 ◽  
Vol 335-336 ◽  
pp. 1385-1390 ◽  
Author(s):  
Shuo Wiei Zhao ◽  
Hui Xu ◽  
Hua Ming Li ◽  
Yuan Guo Xu

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.


2020 ◽  
Author(s):  
Sankara Rao Miditana ◽  
Siva Rao Tirukkovalluri ◽  
Imandi Manga Raju ◽  
Shaik Abdul Alim ◽  
Genji Jaishree ◽  
...  

Abstract The present work mainly aimed to synthesize different weight percentages (0.25-1.00 wt%) of Manganese (Mn2+) and Magnesium (Mg2+) bimetal ions doped TiO2 nanomaterial assisted with different weight percentages (5-15 wt%) of Gemini Surfactant (GS) using sol-gel method. The bimetal doped and undoped TiO2 photocatalysts were characterized by X-ray Diffraction, Scanning Electron Microscopy, Energy Dispersive X-ray Spectroscopy, Fourier Transform Infrared Spectroscopy (FT-IR), UV-Visible Diffused Reflectance Spectroscopy, Transmission Electron Microscopy, Brunauer-Emmett-Teller surface area analyzer, and Photoluminescence Spectroscopy. Characterization results evinced that Mn2+/Mg2+ bimetal ions doping and encapsulation of GS on TiO2 nanoparticles promote the formation of mesoporous multi-particle anatase TiO2 nanocatalysts with a narrowed band gap, less particle size, and high surface area. The surface elemental composition of the 0.25 wt% Mn2+& 1.00 wt% Mg2+ bimetal doped TiO2 in presence of 10 wt% of Gemini surfactant (after calcination) revealed the presence of both the metal dopants Mn2+ and Mg2+ along with the Ti and O and their chemical interactions were further confirmed by FT-IR results. The photocatalytic activity of these catalysts was assessed by the degradation of Methyl Red (MR) using visible light irradiation. To understand the effect of different reaction parameters on the photocatalytic activity of the nanocatalysts such as the dopant concentration, GS concentration, catalyst dosage, solution pH, and initial dye concentrations were investigated and optimized to achieve the best performance. The photoluminescence results conclude that OH radicals are the crucial reactive species responsible for oxidative photocatalytic degradation of MR.


2011 ◽  
Vol 287-290 ◽  
pp. 1640-1645 ◽  
Author(s):  
Min Guang Fan ◽  
Zu Zeng Qin ◽  
Zi Li Liu ◽  
Tong Ming Su

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.


2017 ◽  
Vol 41 (8) ◽  
pp. 475-483 ◽  
Author(s):  
C. Chen ◽  
X. F. Lei ◽  
M. Z. Xue

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.


2021 ◽  
Author(s):  
Sankara Rao Miditana ◽  
Siva Rao Tirukkovalluri ◽  
Imandi Manga Raju ◽  
Shaik Abdul Alim ◽  
Genji Jaishree ◽  
...  

Abstract The present work mainly aimed to synthesize different weight percentages (0.25-1.00 wt%) of Manganese (Mn2+) and Magnesium (Mg2+) bimetal ions doped TiO2 nanomaterial assisted with different weight percentages (5-15 wt%) of Gemini surfactant (GS) using sol-gel method. The bimetal doped and undoped TiO2 photocatalysts were characterized by X-ray Diffraction, Scanning Electron Microscopy, Energy Dispersive X-ray Spectroscopy, Fourier Transform Infrared Spectroscopy (FT-IR), UV-Visible Diffused Reflectance Spectroscopy, Transmission Electron Microscopy, Brunauer-Emmett-Teller surface area analyzer, and Photoluminescence Spectroscopy. Characterization results revealed that mesoporous multi-particle anatase TiO2 nanoparticles with a narrowed band gap, small particle size, and high surface area were formed due to the combined effect of Mn2+/Mg2+ bimetal ions doping and effective encapsulation of GS over the initially formed TiO2 nanoparticles. The surface elemental composition of the 0.25 wt% Mn2+ and 1.00 wt% Mg2+ bimetal doped TiO2 in the presence of 10 wt% of GS (after calcination) revealed the presence of both the metal dopants Mn2+ and Mg2+ along with the Ti and O and their chemical interactions were further confirmed by FT-IR results. The photocatalytic activity of these catalysts was assessed by the degradation of Methyl Red using visible light irradiation. To understand the effect of different reaction parameters on the photocatalytic activity of the nanocatalysts such as the dopant concentration, surfactant concentration, catalyst dosage, solution pH, and initial dye concentrations were investigated and optimized to achieve the best performance. The photoluminescence results conclude that OH radicals are the crucial reactive species responsible for oxidative photocatalytic degradation of Methyl Red.


2021 ◽  
Author(s):  
N Sujatha ◽  
M Meenachi ◽  
S Mohammed Harshulkhanb ◽  
H.H Hegazy

Abstract In later years, numerous viable photocatalysts have been created in order to illuminate the issues of natural toxins. In this work, heterostructured photocatalysts Ag3VO4/g-C3N4 were prepared by effortless hydrothermal route in order to anchor Ag3VO4 on the surface of the g-C3N4 nanosheets. The prepared samples were fairly characterized using X-ray diffraction (XRD), Energy dispersive analysis of X-rays (EDAX), Scanning electron microscopy (SEM), Transmission electron microscopy (TEM), UV-vis diffuse reflectance spectroscopy (UV-DRS), photoluminescence, and X-ray photoelectron spectroscopy (XPS) techniques. The photocatalytic activity of the samples was evaluated by degrading malachite green (MG) and 2,4 dimethyl phenol (DMP) in aqueous solution under visible light irradiation. Compared with Ag3VO4 and g-C3N4, the heterojuncted photocatalyst 50 wt% Ag3VO4/g-C3N4 exhibits the best activity such as high degradation efficiency (99%), high apparent constant (0.0923 min− 1) and long term stability towards DMP under visible light irradiation. The development of a phase scheme heterojunction between Ag3VO4 and g-C3N4 improved the photocatalytic efficiency of Ag3VO4/g-C3N4 composites. Furthermore, the porous structure of g-C3N4 and the effect of Ag surface plasmon resonance (SPR) speed up the isolation and transfer of electron-hole pairs, reducing the likelihood of recombination.


2012 ◽  
Vol 2012 ◽  
pp. 1-7 ◽  
Author(s):  
Quan Gu ◽  
Huaqiang Zhuang ◽  
Jinlin Long ◽  
Xiaohan An ◽  
Huan Lin ◽  
...  

The C-doped CdO photocatalysts were simply prepared by high-temperature solid-state process. The as-prepared photocatalysts were characterized by X-ray powder diffraction (XRD), diffuse reflectance spectroscopy (UV-Vis DRS), scanning electron microscopy (SEM) and X-ray photoelectron spectroscopy (XPS). The results demonstrated that the carbon was doped into CdO, resulting in the red-shift of the optical absorption of CdO. The photocatalytic behavior of CdO and C-doped CdO was evaluated under the visible light irradiation by using the photocatalytic hydrogen evolution as a model reaction. The C-doped CdO photocatalysts had higher photocatalytic activity over parent CdO under visible light irradiation. The results indicated that the H2production was due to the existence of CdS and the enhancement of visible light photocatalytic activity of H2production was originated from the doping of carbon into the CdO lattice. The probably reaction mechanism was also discussed and proposed.


2019 ◽  
Vol 29 (1) ◽  
Author(s):  
Ravi Kumar Mulpuri ◽  
Siva Rao Tirukkovalluri ◽  
Manga Raju Imandi ◽  
Shaik Abdul Alim ◽  
Venkata Divya Lakshmi Kapuganti

AbstractThe present investigation summarizes the synthesis and characterization of zinc and boron co-doped TiO2 nano catalyst by sol gel method at relatively low temperature and explored the optimum reaction parameters for the degradation of Acid Red 6A (AR 6A) under visible light irradiation. The structural, morphological, surface properties of the synthesized photocatalysts were characterized by X-Ray Diffraction, Scanning Electron Microscopy-Energy Dispersive X-ray Spectroscopy, Transmission Electron Microscopy, Brunauer-Emmett-Teller, UV-Vis-Diffuse Reflectance Spectroscopy, X-ray Photo Electron Spectroscopy and Fourier Transform-Infra Red Spectroscopy. The findings of the characterization results revealed that Zn2+ ion was substitutionally doped into TiO2 lattice by replacing Ti4+ ion and a part of the boron substituted the oxygen in TiO2 lattice and the remaining amount was converted to B2O3 due to calcinations at 450 °C. The degradation of AR 6A was achieved at optimum reaction parameters, such as pH = 6 with a catalyst dosage 100 mg L−1 for the degradation of 5 mg L−1 of dye solution.


Author(s):  
Yaping Guo ◽  
Jianyang Sun ◽  
Hui Chang ◽  
Xu Zhao

A simple, effective and environmental-friendly method was adopted for enhancing the photocatalytic activity of g-C3N4 in the reduction of aqueous Cr(Ⅵ) under visible-light irradiation. The enhancement was achieved via treatment of g-C3N4 in organic solvent with addition of NaOH particles by ultrasonic process for two hours. The results demonstrated that the treated g-C3N4 exhibited much higher photocatalytic activity than pristine g-C3N4 in the reduction of Cr(VI) . Under visible light irradiation for 120 min, the reduced ratios of Cr(VI) with the initial concentration of 50 mg/L in the presence of the treated g-C3N4and pristine g-C3N4 were 100% and 37.1%, respectively. With the addition of fulvic acid, Cr(VI) was efficiently removed at 40 min. Based on the characterization results of the structures and other physiochemical properties of the treated g-C3N4 and pristine g-C3N4 by X-ray diffraction, scanning electron microscopy, transmission electron microscopy and UV Vis diffuse reflectance, the possible reasons responsible for the enhanced photocatalytic activity of the treated g-C3N4 were proposed. The yield and mechanism of different exfoliation methods were compared by semi-quantitative method.


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