Synthesis and photocatalytic performance of Ag-TiVOX nanocomposite
- Authors: Ntobeng, Mahubedu Khutso , Imoisili, Patrick Ehi , Jen, Ten-Chien
- Date: 2020
- Subjects: Titanium , Nanocomposite , Methylene blue
- Language: English
- Type: Article
- Identifier: http://hdl.handle.net/10210/458235 , uj:40693 , Ntobeng, M.K., Imoisili, P.E., Jen, T.: Synthesis and photocatalytic performance of Ag-TiVOX nanocomposite. DOI: https://doi.org/10.1016/j.jksus.2020.08.021
- Description: Abstract: A silver, vanadium and silver/vanadium doped titanium dioxide (TiO2, Ag-TiO2, V-TiO2 and Ag-TiVOX) nanocomposite photocatalyst was achieved via a modify sol–gel and hydrothermal method. Structural analysis by X-Ray Diffraction (XRD) depicted the lattice fringes for both anatase and rutile in its crystalline phase in the synthesized nanocomposites. Surface areas (SBET) analysis shows that surface area of synthesized Ag-TiVOX is 46.01 m2/g, compare to TiO2 64.75 m2/g, Ag-TiO2 61.33 m2/g and V-TiO2 62.73 m2/g. Optical absorption results demonstrated by UV–Visible Spectroscopy (UV–Vis) shows that the effects of Ag and V doping was a shift in spectrum to the visible light region, enhancing the visible light absorption capacity of the synthesized photocatalyst. The optical absorption of Ag-TiVOX achieved a reduced bandgap energy of 2.2 eV, as compared to Ag-TiO2 (2.8 eV), V-TiO2 (2.3 eV) and TiO2 (2.9 eV). Morphological characterization by Transition Electron Microscope (TEM) and Scanning Electron Microscope (SEM), depicting a cluster composed of spherical aggregates particles of non-uniform diameter nanoparticles with particle size ranging between 10 and 50 nm. Synthesized Ag-TiVOx demonstrated remarkable photocatalytic capabilities under visible light irradiation, as 99.83 percent of methylene blue (MB) degradation was accomplished during the first 15 min. Impact of Ag and V doping of TiO2 showed enhancement in the photocatalytic activity, reporting excellent removal rates and achieving well desirable decline in the band gap energy.
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Facile fabrication of vanadium sensitized silver titanium oxides (V-Ag/TiO2) photocatalyst nanocomposite for pollutants removal in river water
- Authors: Ntobeng, Mahubedu Khutso , Imoisili, Patrick Ehi , Jen, Tien-Chien
- Date: 2020
- Subjects: Photocatalyst , Nanocomposite , Sol gel
- Language: English
- Type: Article
- Identifier: http://hdl.handle.net/10210/461414 , uj:41097 , Citation: Ntobeng, M.K., Imoisili, P.E. & Jen, T.C. 2020. Facile fabrication of vanadium sensitized silver titanium oxides (V-Ag/TiO2) photocatalyst nanocomposite for pollutants removal in river water. , DOI: https://doi.org/10.1016/j.mssp.2020.105569
- Description: Abstract: Please refer to full text to view abstract.
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Visible light photocatalytic degradation of pollutants in surface water, Limpopo, South Africa
- Authors: Ntobeng, Mahubedu Khutso
- Date: 2021
- Subjects: Water - Purification - Photocatalysis , Titanium dioxide
- Language: English
- Type: Masters (Thesis)
- Identifier: http://hdl.handle.net/10210/481968 , uj:43688
- Description: Abstract: A novel silver and vanadium co-doped titanium dioxide (Ag, V-TiO2) photocatalyst was achieved by a simple sol-gel hydrothermal method. The co-doped Ag, V-TiO2 photocatalyst exhibited high photocatalytic activity as compared to synthesised titanium dioxide (TiO2), silver doped titanium dioxide (Ag-TiO2) and Vanadium dope titanium dioxide (V-TiO2). The co-doped Ag, V-TiO2 illustrated a shift in the absorption edge, enhancing the visible light absorption capacity. The optical absorption of co-doped Ag, V-TiO2 achieved a reduced band gap energy (Eg) of 2.2eV as compared to Ag-TiO2 (2.8eV) and V-TiO2 (2.3eV), while TiO2 obtained a band gap energy of 2.9eV. The codoped photocatalyst inherited morphological and structural compositions that depicted the lattice fringes for both anatase and rutile in its crystalline phase. This analysis was in good agreement with results obtained by X-ray diffraction (XRD) characterisation techniques. Co-doped Ag, V-TiO2 showed excellent photocatalytic abilities under visible light irradiation. The degradation of Methylene blue (MB) was achieved within the first 15min. The kinetic study for the degradation of (MB) followed the pseudo-first order reaction. More interestingly, it was found that the photocatalytic degradation performance had a direct relation with the intensity plane ratio corresponding to [101] / [110]. The effects of co-doping showed a shift in spectrum to the visible light region. This was evident in the study of binding energies presented by X-ray photoelectron spectroscopy (XPS). Thus, the effects of co-doping TiO2 showed achieving well desirable reduction in the band gap energy and enhancements in the photocatalytic activity, reporting excellent removal rates of 99.33%. The evaluation of photocatalytic degradation of pollutants in water from River water in Limpopo (Mathibeng) and Mpumalanga Witbank (Ezinabeni) gave a clear indication that the synthesized Ag, V co-doped TiO2 photocatalyst was effective in removing nitrate, nitrites, humic substance, aromatics, Trihalomethanes (THM) and organic concentration. Furthermore, the GC-MS analysis of the water samples proved the organic pollutants removal with a removal efficiency of 77.84%. These finding open up a solution for the treatment of surface and river water where the concentration of pollutants are low. , M.Ing. (Mechanical Engineering)
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