Photocatalytic Activity Of SrTiO3 Research Articles

Investigation of doping effect on the local structure and photocatalytic activity of SrTiO3

Investigation of doping effect on the local structure and photocatalytic activity of SrTiO3

“Perovskite SrTiO3 for photo catalytic and optoelectronic applications”

In this work, we report the synthesis of SrTiO3(STO) nanoparticles by solid-state method for photocatalytic applications. The samples were calcinated at different temperatures to obtain a single phase. The prepared samples were studied using various analytical techniques such as XRD, DRS, SEM/EDAX, and FTIR. XRD analysis before and after high-temperature calcination indicates eliminating impurities from the sample. FTIR spectroscopy also correlates with the formation of pure SrTiO3. SEM analysis shows the formation of cube-like nanostructures and a bandgap of 3.2 eV was observed from Diffuse Reflectance Spectroscopy studies. The photocatalytic activity of SrTiO3 towards methylene blue was studied for various catalyst concentrations. The SrTiO3 catalyst attained a degradation efficiency reaching up to 83 % in 120 min. IV measurements of the SrTiO3 thin films reveal the potential optoelectronic applications.

Photocatalytic Activity of SrTiO3 and BaTiO3 Nanostructures, Formed by the Sol-Gel Method, in the Process of Nitrogen Dioxide Decomposition

Photocatalytic Activity of SrTiO3 and BaTiO3 Nanostructures, Formed by the Sol-Gel Method, in the Process of Nitrogen Dioxide Decomposition

Preparation, characterization and photocatalytic activity of SrTiO3 and Ag2O/SrTiO3 nanomaterials

The pure SrTiO3 nanoparticles were synthesized by sol-gel method and Ag2O loaded SrTiO3 (Ag2O/SrTiO3) was prepared by precipitation method. The obtained samples were characterized with powder X-ray diffraction (XRD), transmission electron microscope (TEM) and UV-visible diffuse reflection spectrum (DRS). The effect of Ag2O loading on the photocatalytic activity of Ag2O/SrTiO3 nanoparticles for the degradation of methyl orange (MO) as amodel pollutant under visible light irradiation was studied. Compared with pure SrTiO3 nanoparticles, the Ag2O/SrTiO3 nanoparticle displayed higher photocatalytic activity for the degradation of methyl orange and the 5 % Ag2O/SrTiO3 photocatalyst exhibited the highest photocatalytic activity.

RETRACTED: Synthesis and post-annealing of Ag nanoparticles decorated urchin-like SrTiO3 particles for enhanced electron/hole separation and photocatalytic activity

Abstract Ag nanoparticles decorated urchin-like SrTiO3 particles were synthesized by Atomic Layer Deposition (ALD). The morphology and crystal structures of SrTiO3 and SrTiO3/Ag particles were determined by SEM, TEM, and XRD. The specific surface area of the samples was studied by N2 adsorption/desorption. Finally, the photocatalytic activity of SrTiO3 and SrTiO3/Ag particles was determined by the decomposition of RhB dye. The results indicated that when the ALD deposition cycle was 20, the SrTiO3/Ag composite showed the best photocatalytic performance, which was due to the increased electron/hole separations. Moreover, post-annealing could further increase the photocatalytic activity of SrTiO3/Ag, which could be explained by the increased interaction and decreased charge transfer resistance between SrTiO3 and Ag.

Effect of Na‐Doping on Electron Decay Kinetics in SrTiO3 Photocatalyst

AbstractPhotocatalytic water splitting by solar light is an environment‐friendly means for generating hydrogen as energy resources. For practical use, photocatalysts with higher activity are desired. Recently it was found that the photocatalytic activity of SrTiO3 is remarkably improved by Na‐doping. However, why Na‐doping enhances the activity has not been well understood. In this work, we found that Na‐doping in SrTiO3 introduces new mid‐gap states. Transient absorption measurements revealed that photoexcited electrons were trapped into these states within ∼20 ps after excitation. These trapped electrons have longer lifetime than those in undoped SrTiO3, and number of surviving electrons in microseconds increased ∼15 times. These electrons are trapped at the mid‐gap states, but still keep reactivity with reactant molecules. Furthermore, they were effectively captured by H2‐evolution cocatalyst, indicating that they can participate in steady‐state reactions. This work emphasizes the important role of electron‐trapping states introduced by doping on photocatalytic activity.

Preparation of a new magnetic and photo-catalyst CoFe2O4–SrTiO3 perovskite nanocomposite for photo-degradation of toxic dyes under short time visible irradiation

CoFe2O4 nanostructures were first synthesized via a simple and high-quality hydrothermal method. Strontium titanate (SrTiO3) nanoparticles were then prepared using the sol-gel method. In the last step, magnetic and photocatalytic nanocomposites of CoFe2O4–SrTiO3 and SrTiO3: N–CoFe2O4 were synthesized successfully also by sol-gel method. To characterize the purity, morphology, and particle size of nanomaterials, X-ray diffraction (XRD), scanning electron microscopy (SEM) and Fourier transform infrared (FT-IR) spectroscopy, were employed. Vibrating sample magnetometer (VSM) studies show the super-paramagnetic and ferromagnetic property of the cobalt ferrite nanostructures. Photocatalytic activity of SrTiO3, SrTiO3: N nanoparticles and nanocomposites were evaluated using UV–Vis spectroscopy for degradation of acid brown and acid black (azo dyes) under ultraviolet and visible light. The CoFe2O4–SrTiO3 nanocomposites can lead to efficient charge separation and as a result having photocatalytic activity higher than SrTiO3 nanoparticles under UV light. By nitrogen doping to the SrTiO3 nanoparticles, this photocatalyst is activated with visible light because maximum point of the valence band will be transferred to the lower potential and energy gap is decreased. Due to the separation of charge compared to the SrTiO3: N nanoparticle, the SrTiO3: N–CoFe2O4 nanocomposite has high photocatalytic efficiency for destroying of pollutants.

Photocatalytic activities of sulfur doped SrTiO3 under simulated solar irradiation

S-doped SrTiO3 was synthesized by the solid state reaction method between S and SrTiO3 power under the N2 flow. The effect of temperature, calcination time and S-content on the formation and photocatalytic activity of SrTiO3 were investigated. The morphology and properties of obtained powders were characterized by XRD, UV-DRS, UV-VIS, SEM, BET. The photocatalytic activities of S-doped SrTiO3 was also investigated through the decomposition of methylene blue. As a result, the 10 %S-doped SrTiO3 contributed to the decrease of band gap energy to 2.73 eV and enhanced the photocatalytic activity for methylene blue degradation of 74.5 % after 180 min irradiation.

Glycine–nitrate-based solution-combustion synthesis of SrTiO3

In this paper, we describe the glycine–nitrate-based solution combustion synthesis of SrTiO3 nanoparticles. The effects of the fuel ratio, φ, and washing treatment by HNO3 on the size, morphology, and crystalline structure of the synthesized particles were investigated. The photocatalytic activity of the final samples was also evaluated by measuring the photodegradation of methylene blue. The samples, which were calcined at 1000 °C for 10 h after combustion synthesis, were mainly SrTiO3. When φ was increased, the number of pores in the sample was increased because of the increase in volume of ejected gas. Additionally, the initial particle size decreased with increasing φ because glycine functioned not only as a fuel but also as a dispersant and stabilizer. After washing in a HNO3 solution, the porous structure decomposed to particles with high crystalline structure. The photocatalytic activity of SrTiO3 was significantly improved by HNO3 washing owing to the elimination of impurities, the increase in surface area, and the uncovering of the surface that consisted of (100) planes.

Molten Salt Synthesis of SrTiO3 Using TiO2 with Different Morphology as a Precursor

SrTiO3 powders were synthesized by molten salt method with homemade different morphology TiO2 in the eutectic NaCl-KCl salts. The phases, crystallite sizes, morphologies and band gap of the as-prepared products were characterized using X-ray powder diffraction (XRD), scanning electron microscopy (SEM), UV-Vis diffuse reflectance spectra respectively. The photocatalytic activity of SrTiO3 with different morphology was measured by CO2 reduction device. The morphologies of the as-synthesized SrTiO3 depended on the morphologies of TiO2 precursors, indicating that the formation process of SrTiO3 in the molten salts was mainly controlled by the template formation mechanism. The results show that compared with different morphology SrTiO3, sphere-shaped SrTiO3 exhibit best activity loaded 5%Cu, showed the least Eg and crystallite size. The photocatalytic activity has something to do with the crystallite and the Eg with different morphology.

Fabrication of ZnO/SrTiO3 nanoarrays and its photoelectrochemical performances

The ZnO/SrTiO3 nanomaterials were fabricated by a chemical conversion hydrothermal method in order to utilize the high electron transfer rate of one-dimensional ZnO nanorods and photocatalytic activity of SrTiO3. The technological parameters, such as TiO2 sol concentration, TiO2 sol dipping cycle, Sr(NO3)2 concentration and reaction temperature, were investigated in the synthetic process and the reaction mechanism of the ZnO/SrTiO3 nanomaterials was proposed. A photocurrent density of 7.53 mA/cm2 was obtained for the as-prepared ZnO/SrTiO3 photocatalyst, attributed to its improved absorption spectrum and appropriate nanostructure, which indicates a potential application in photoelectrochemical water splitting.

Roles of Cr3+ doping and oxygen vacancies in SrTiO3 photocatalysts with high visible light activity for NO removal

The photocatalytic degradation of nitrogen monoxide (deNOx) in the gas phase was investigated in a continuous reactor using a strontium titanate-based semiconductor, CaAl2O4:(Eu, Nd)/Cr-doped SrTiO3, and CaAl2O4:(Eu, Nd)/oxygen vacancy-induced SrTiO3 catalysts. Cr doping and oxygen vacancies generation could narrow the band gap of SrTiO3 and affect the photocatalytic performance to varying degrees. The photocatalytic activity of SrTiO3 toward LED light (445nm)-induced photocatalytic deNOx can be greatly improved by the nonstoichiometric synthesis of SrTiO3, mainly due to oxygen deficiency generation. CaAl2O4:(Eu, Nd)/Cr-doped SrTiO3 composites possessed superiority in NO removal under persistent fluorescence irradiation (440nm) after the mercury lamp with wavelength larger than 290nm was turned off.

Visible light photocatalytic activity induced by the carboxyl group chemically bonded on the surface of SrTiO3

Strontium titanate nanoparticles were synthesized by a microwave-assisted solvothermal reaction of SrCl2·6H2O, Ti(OC3H7)4 in KOH methanol–oleic acid solution. The products were characterized by TG-DTA, XRD, TEM, BET surface area and XPS. The photocatalytic activity was determined by DeNOx ability using LED lamps with various wavelengths such as 627nm (red), 530nm (green), 445nm (blue) and 390nm (UV). The nanoparticles of perovskite type SrTiO3 with the particle size of 15–18nm were successfully synthesized. The photocatalytic activity of SrTiO3 under visible light (λ=530nm) irradiation could be generated by modification of the surface with the carboxyl group (–COO) from oleic acid which enabled the absorption of visible light.

Density functional characterization of the electronic structure and optical properties of Cr-doped SrTiO3

First-principles density functional theory electronic structure calculations were carried out for Cr-doped SrTiO3 to evaluate the effect of Cr-doping on the band gap states and the photocatalytic activity of SrTiO3. The defect formation energy is also investigated to determine the energy required for Cr-doping. Our results indicate that substituting Cr for Sr requires smaller formation energy than substituting Cr for Ti in the Cr-doped SrTiO3 structures and the Cr atoms energetically prefer to partially take up some Sr sites, simultaneously partially some Ti sites. Some Cr 3d gap states appear near the bottom of the conduction band in the Cr-doped SrTiO3 structures, which results in the decreased electron transition energy and thus the visible light absorption observed in the experiment. The correlations between the doped Cr atoms at different sites and the environmental O atoms may be responsible for the differences in the visible light photocatalytic activities for the doped SrTiO3. Further research demonstrates that different dopant concentrations in Cr-doped SrTiO3 do not bring significant changes in the electronic characteristics but may change a little the electron transition energy and weaken photocatalytic activity under visible light.