No abstract

In this paper, we have reported a novel photocatalytic study of vanadium-doped SnO2 nanoparticles (SnO2: V NPs) in rhodamine B degradation. These NPs have been prepared with vanadium concentrations varying from 0% to 4% via the coprecipitation method. Structural, morphological, and optical properties of the prepared nanoparticles have been investigated by X-ray diffraction (XRD), Fourier transform infrared (FTIR) spectroscopy, transmission electron microscope (TEM), and UV-Vis and photoluminescence (PL) spectroscopy. Structural properties showed that both undoped and SnO2: V NPs exhibited the tetragonal structure, and the average crystal size has been decreased from 20 nm to 10 nm with the increasing doping level of vanadium. Optical studies showed that the absorption edge of SnO2: V NPs showed a redshift with the increasing vanadium concentration. This redshift leads to the decrease in the optical band gap from 3.25 eV to 2.55 eV. A quenching in luminescence intensity has been observed in SnO2: V NPs, as compared to the undoped sample. Rhodamine B dye (RhB) has been used to study the photocatalytic degradation of all synthesized NPs. As compared to undoped SnO2 NPs, the photocatalytic activity of SnO2: V NPs has been improved. RhB dye was considerably degraded by 95% within 150 min over on the SnO2: V NPs.

High efficient and large surface area of titanium doped tin dioxide (SnO2) based photocatalysts with various titanium doping contents varying from 0 to 4 mol% have been successfully prepared via a facile, low cost and eco-friendly co-precipitation method. Structural, morphological, textural, microstructural and optical properties of the prepared Ti-SnO2 nanoparticles (NPs) have been investigated by X-ray diffraction (XRD), scanning electron microscope (SEM), the Brunauer–Emmett-Teller (BET) method, Raman spectroscopy, Fourier transform infrared (FTIR), UV-Vis spectroscopy and photoluminescence (PL) spectroscopy. It was found that both undoped and Ti doped SnO2 NPs were crystallized in tetragonal structure and the crystallite sizes have been reduced from 19.9 nm for undoped SnO2 NPs to 13.1 nm for SnO2: Ti 4%. As compared to pure SnO2, a decrease in size and a uniform distribution of spherical aggregates for 4% Ti doped SnO2 sample have been noticed. Nitrogen (N2) adsorption-desorption isotherms of all synthesized NPs indicate that each nanopowder showed a IV type- isotherm with a hysteresis loop resulted in a typical porous materials containing macropores and mesopores. The raman spectra was marked with the appearance of three well resolved peaks including one intense peak centered at 633 cm−1 and two other peaks at about 475 cm−1 and 772 cm−1 which might be ascribed to the characteristic modes of of the SnO2 rutile-type. FTIR spectra of Ti doped SnO2 NPs show a broad band situated in the region from 630 cm−1 to 625 cm−1 for all Ti–SnO2 samples which could be assigned to the stretching vibrations of Sn–O–Sn. Optical studies revealed that the absorption edge of SnO2: Ti NPs showed a redshift with rising titanium concentration. This redshift resulted in a decrease in the optical band gap from 3.31 eV for pure SnO2 to 2.87 eV for 4% Ti doped SnO2 nanoparticles respectively. Rhodamine B dye (RhB) has been adopted to study the photocatalytic degradation of all synthesized Ti–SnO2 NPs. Pure SnO2 NPs has an intrinsic large band gap and it was sensitive to UV light. Thus, pure SnO2 NPs display higher UV photocatalytic performance for decomposing the RhB. Titanium incorporation into SnO2 has widely improved its photocatalytic performance towards RhB photodegradation under UV and Visible light irradiations. Precisely, the 4% Ti–SnO2 based photocatalyst display the highest photacatalytic activity and can degrade both of 95% and 52% of RhB dye within 120 min respectively under UV and visible light irradiations. The enhanced photocatalytic activity of the 4% doped SnO2 photocatalyst was further proved with the minimum PL intensity. The homogeneous incorporation of low Ti contents into the SnO2 matrix allow to a significant reduce in the band gap leading to an efficient separation of photogenerated electron-hole pairs and consequently improves the absorption capability in the visible light.

No abstract

Silver-doped zinc oxide (SZO) thin films have been deposited onto indium-doped tin oxide substrates (ITO) using sol–gel spin-coating technique with different Ag doping content (1, 2 and 5% Ag). The effect of silver incorporation on structural, morphological, optical and photoelectrochemical (PEC) properties of the SZO films was investigated. Ag incorporation resulted in an enhanced grain size and thickness of elaborated SZO films. Scanning electron micrographs exhibited a uniform distribution of spherical grains with particle size increment after doping. Band gap energies were found to increase after Ag doping. Photoluminescence (PL) measurements revealed that the energy band gaps of the films were in the UV region. As compared to pure ZnO thin film, the samples are more photoactive, and the film containing 2% Ag yielded the highest photocurrent. A correlation study between PEC and PL measurements of Ag-doped ZnO/ITO photoanode leads to a reverse variation. Charge transfer processes at the ZnO–electrolyte interface were identified by electrochemical impedance spectroscopy.