Photocatalytic Activity Of Fe3 Research Articles

Influence of Fe3+ ion doping on the luminescence emission behavior and photocatalytic activity of Fe3+, Eu3+-codoped TiO2 thin films

Abstract Thin films of Fe3+ doped TiO2:0.01Eu3+ nanoparticles were coated by sol-gel spin coating technique on glass substrates. The studies carried out by using X-ray Diffractometer, SEM-EDX, HRTEM, spectroscopic ellipsometer, Raman, EPR, UV–Vis, and fluorescence spectrometer techniques. The crystalline structure and phase formation of Fe doped TiO2:0.01Eu3+ nanoparticles were investigated using X-ray Diffractometer. The HRTEM pictures of 3%, and 5% Fe doped TiO2:0.01Eu3+ films confirmed that the particle size is about 11 nm and 9.5 nm respectively. Raman spectroscopy was used to study the phase identification and vibrational modes present in Fe, Eu codoped TiO2 films. The band gap declined with cumulative amount of Fe3+. The EPR analysis endorses that the Fe3+ ions are successfully doped in the lattice of Titania by replacing Ti4+ ions and formation of oxygen vacancies and Ti3+ sites. With 393 nm excitation, the Fe doped TiO2:0.01Eu3+ nanoparticles show characteristic photoluminescence in the visible range. The strong luminescence emission at 614 nm is related to the 5D0 → 7F2 ED transition. The emission peak intensity declined with an increase in the amount of Fe3+. J–O and radiative parameters of Fe doped TiO2:0.01Eu3+ films obtained from the emission spectra. These nanophosphor films having significant CIE chromaticity coordinate (x, y) values with high color purity might have potential applications in solid-state display devices. The photocatalytic activity (PCA) of Fe, Eu codoped TiO2 nanostructured films were estimated using decolorization of methylene blue (MB) and methyl orange (MO). Fe, Eu codoped TiO2 films exhibit strong photocatalytic performance than undoped and single doped TiO2 films. The degradation efficiencies significantly increase with an increase in Fe3+ doping concentration reached maximum at 3%Fe doping and then reduces gradually at high concentrations due to the formation of recombination centers for charge carriers at a higher amount of Fe doping.

Effect of Sb5+ codopant ions on the ultraviolet photocatalytic activity of Fe3+-modified anatase

The presence of antimony in (x at% Fe3+ + x at% Sb5+):TiO2 powder samples containing equimolar amounts (0.15 ≤ x ≤ 1) of the dopant cations was accompanied by an increase in the reaction rate constant k of the decolorization of methyl orange. Nevertheless, the increase in the rate of this test reaction, consistent with a decrease in the number of charge balance oxygen vacancies VO imputable to the codoping with Sb5+, rapidly weakened with increasing x. This effect is accounted for by the increased number of Fe3+–VO associates slowing down the outward diffusion of VO vacancies and, consequently, their rate of annealing in the studied catalyst.

Effect of charge balance vacancies on the ultraviolet photocatalytic activity of Fe3+-doped anatase

The presence of Fe3+ dopant ions rastically decreases the activity of TiO2 powders in the photocatalytic decolorization of methyl orange. A comparison of the photocatalytic activities of the 0.6 at% Fe3+: TiO2 and 0.6 at% Cr3+: TiO2 samples before and after their hydrogen annealing shows that this negative effect is mainly due to the formation of charge balance oxygen vacancies VO, and it does almost not depend on the physicochemical properties of M3+ dopants. The 57Fe Mossbauer spectrum of 2 at% Fe3+: TiO2 indicates that nearly every other Fe3+ ion introduced into TiO2 possesses a vacancy VO in its nearest surrounding.

Structural, optical properties and photocatalytic activity of Fe3+ doped TiO2 thin films deposited by sol-gel spin coating

Nanocrystalline TiO2: Fe3+ films were deposited using a simple spin coating technique. The effect of Fe3+ on spectroscopic features and photocatalytic activity of films were studied using X-ray diffractometer (XRD), scanning electron microscope (SEM), Energy dispersive X-ray (EDX), high-resolution transmission electron microscope (HR-TEM), Raman spectrometer, UV–Vis and fluorescence spectrophotometer. The XRD of all the TiO2: Fe3+ films exhibits a decrease in the crystallite size with an increase in Fe3+ concentration. The Fe3+ doped TiO2 nanocrystals exhibited a high specific surface area. The HR-TEM images of 1% and 7% Fe doped TiO2 thin films confirmed the average particle size is about 14 and 8 nm respectively. The Raman modes of vibrations present in the TiO2:Fe3+ films also confirms the formation of the anatase phase. The optical bandgap energy of titania decreases from 3.32 to 2.57 eV. The luminescent emission intensity of TiO2: Fe3+ films decreased compare to pure titania film. Moreover, the photocatalytic activity (PCA) of TiO2:x%Fe3+ (x = 0, 1, 3, 5, 7 and 10) catalysts were determined by the decomposition of methylene blue (MB) under irradiation of visible light. The observed results revealed that the optimized Fe3+ doped TiO2 film displayed high PCA. The enhancement of PCA of the films is due to the effect of Fe doping.

Preparation and Catalytic Performance of Fe3+ Doped Nano-materials

Fe3+-doped nano-TiO2 powders were prepared by sol-gel method. The photocatalytic activity of Fe3+-doped TiO2 nanoparticles was studied by using UV lamp as light source and methylene blue as degradation target. The photocatalytic activity of Fe3+-doped TiO2 was studied by degradation of 4L methylene blue solution with initial concentration of 10mg · L - 1. The results show that the photocatalytic activity of TiO2 can be improved by the addition of Fe3+. When the molar ratio of Fe3+ is 0.5-1%, the calcination temperature is 500 ℃. The photocatalytic degradation of methylene blue is the best.

A novel synergy of Er3+/Fe3+ co-doped porous Bi5O7I microspheres with enhanced photocatalytic activity under visible-light irradiation

Uniform porous Bi5O7I (BOI) microspheres photocatalysts co-doped with Fe3+ and Er3+ were synthesized by a solvothermal-thermal decomposition method, in which Er3+ with upconversion properties could transform infrared light beyond the absorption edge of Bi5O7I into visible light, and also activate the Fe3+-doped Bi5O7I (Fe-BOI). The photocatalytic activities of the photocatalysts were evaluated by the degradation of three typical colorless model pollutants, i.e., phenol, bisphenol A (BPA), and chloramphenicol (CAP), under visible light irradiation (800nm>λ>400nm). The results showed that the photocatalytic activity of Fe3+/Er3+ co-doped Bi5O7I (Er/Fe-BOI) was much higher than that of the undoped, Fe3+-doped and Er3+-doped Bi5O7I photocatalysts. In addition, Fe3+/Er3+ co-doped Bi5O7I exhibited photocatalytic activity under a 3W LED lamp (red light, λ=630nm) with the wavelength beyond the absorption edge of Bi5O7I, which further testified that the upconversion effect of Er3+ generates the enhanced photocatalytic activity of Bi5O7I. Photodegradation mechanism was systematically studied by using various radical quenchers and it was revealed that photogenerated holes (h+) and superoxide radicals (O2−) actively participated, whereas hydroxyl (OH) radicals had negligible contribution in photodegradation of phenol.

Effects of surface hydroxyl group density on the photocatalytic activity of Fe3+-doped TiO2

The aim of the work is to study the effects of oxygen vacancy and surface hydroxyl group density on the photocatalytic activity of Fe3+-doped TiO2, and to investigate how the titanium dioxide doped with different levels of the Fe3+ influenced their physical and chemical characterizations. The photocatalysts were characterized by X-ray diffraction (XRD), thermogravimetric analysis (TGA), electron spin resonance (ESR), X-ray photoelectron spectroscope (XPS) and Fourier transform infrared (FTIR) spectra. The results revealed that adsorbed hydroxyl group density significantly influenced the photocatalytic activity, and a small amount of Fe3+ can act as a photo-generated hole and a photo-generated electron trap and inhibit the electron–hole recombination. The 0.10%-Fe3+-TiO2 with the highest surface hydroxyl group density revealed the maximum rate constant of 0.716 and the optimal photocatalytic degradation of MB. As Fe3+ doping levels are larger than 0.10%, the cluster of FeTi′–V¨O–FeTi′ generated gradually. This implied that an excessive amount of Fe3+ doped into TiO2 is detrimental to the photocatalytic activity due to the formation of FeTi′–V¨O–FeTi′ clusters and enhances the recombination of photogenerated electrons and holes.

Synergic effect of cation doping and phase composition on the photocatalytic performance of TiO2 under visible light

The synergic effect of cation doping and phase composition for the further improvement of the photocatalytic activity of TiO2 under visible light is reported for the first time. Fe3+ and Sn4+ co-doped TiO2 with optimized phase composition were synthesized through a simple soft-chemical solution method. The visible-light-driven photocatalytic activity of Fe3+ and Sn4+ co-doped TiO2 was 5 times of that of Evonik P25 TiO2 using degradation of methylene blue as model reaction. The synthesized photocatalysts were characterized by powder X-ray diffraction, UV–Vis diffuse reflectance spectroscopy, X-ray photoelectron spectroscopy, 119Sn Mössbauer spectroscopy, and X-ray absorption fine structure spectroscopy. It is indicated that Sn4+ doping can facilitate the phase transition from anatase to rutile. The different ratios of anatase and rutile can be achieved by tuning the amount of Sn4+ doped into the lattice. Furthermore, the doping of Sn4+ into TiO2 lattice can stabilize the phase composition when Fe3+ is co-doped. In the Fe3+ and Sn4+ co-doped TiO2, Sn4+ is mainly used to tune and stabilize the phase composition of TiO2 and Fe3+ acts as a doping cation to narrow the band gap of TiO2. Both band gap and phase composition of TiO2 can be tuned effectively by the simultaneous introduction of Fe3+ and Sn4+. The synergic effect of optimized phase composition (anatase/rutile=25/75) and narrowed band gap should be the two main reasons for the promoted photocatalytic activity of TiO2 under visible light.

The effect of vinyl-containing ionic liquid on the photocatalytic activity of iron-doped TiO2

Visible light responsive iron-doped TiO2 (Fe3+/TiO2-IL) was synthesized by sol–gel method using 1-vinyl-3-propylimidazolium iodide (VPIM+I−) as a reaction medium. VPIM+I− not only made the morphological and structural changes of Fe3+/TiO2-IL, but also extended its absorption edge to the visible light region. The photocatalytic activity of Fe3+/TiO2-IL was tested in the degradation of 2-nitrophenol under simulated solar light irradiation. The photocatalytic activity of Fe3+/TiO2-IL was higher than the samples prepared in the reaction medium without VPIM+I−. Moreover, the effect of pH and H2O2 on the photocatalytic activity of Fe3+/TiO2-IL was also investigated. Fe3+/TiO2-IL showed high photocatalytic activity in acidic environment, and H2O2 had a dual effect on the photocatalytic activity Fe3+/TiO2-IL.

Photocatalytic Activity and Antibacterial Behavior of Fe3+-Doped TiO2/SnO2 Nanoparticles

Problem statement: Since bacteria mainly causes damage on fresh vegetables and fruits during transportation to market, anti-bacterial TiO2 photocatalyst was applied for their packaging films. However, it has been known that pure TiO2 exhibits low photocatalytic property due to rapid recombination of photo-activated electrons and holes. Doping with metal or metal oxide shows the improvement of photocatalytic activity and disinfection effect. Approach: Fe3+ was considered to dope into TiO2/3SnO2 photocatalyst in order to enhance the photocatalytic property and bacterial inactivation efficiency. The Fe3+ doped TiO2/3SnO2 nanoparticles were prepared by sol-gel method and calcined at 400 °C for 2 h. The synthesized powders were characterized by XRD, BET and SEM. Photocatalytic activity and bacteria killing effect were determined by means of degradation of methylene blue solution and inactivation of E. coli bacteria, respectively. These tests were performed under UV and visible light irradiations. Results: Fe3+ doping into TiO2/3SnO2 has an effect on inhibition of anatase crystal growth, led to the enlargement of the composite specific surface area. Therefore, the photocatalytic activity of Fe3+ doped TiO2/3SnO2 composite in proper concentration was greater than those of pure TiO2 and TiO2/3SnO2 and 0.5 mol% Fe3+ doping exhibited the highest photocatalytic activity and E.coli inactivation efficiency. The E. coli was completely killed within 90 min under UV irradiation or 99.7% inactivated under visible light exposure. Conclusion: Fe3+ doped TiO2/3SnO2 nanoparticles were successfully synthesized and identified as 100% anatase phase. The 0.5mol% Fe3+-doped TiO2/3SnO2 which has particle size of 12.89 μm and specific surface area of 117.61 m2 g-1, exhibited the highest activity and disinfection efficiency. An attractive feature of Fe3+ doped TiO2/3SnO2 photocatalytic disinfection is its potential to be activated by visible light. Therefore, these composite TiO2 nanoparticles can be utilized for fresh food packaging films.

Bactericidal and photocatalytic activity of Fe3+-TiO2 thin films prepared by the sol-gel method

Pure TiO2 thin films and iron doped TiO2 thin films on glass substrate were prepared by sol-gel method, and characterized by X-ray diffractometer (XRD), thermo-gravimetric analysis (TG-DSC), high resolution transmission electron microscope (HRTEM), scanning electron microscope (SEM) and UV-Vis spectroscopy, respectively. The experimental results show that the pure TiO2 thin films and iron doped TiO2 thin films can destroy most of the escherichia coli and bacillus subtillis under the irradiation of 365 nm UV-light. However, the iron doped TiO2 thin film is a better photocatalyst than pure TiO2 thin film. The ultrastructural studies provide direct evidences for understanding the bactericidal mechanism of the TiO2 photocatalyst.