scholarly journals Ethanol-Quenching Introduced Oxygen Vacancies in Strontium Titanate Surface and the Enhanced Photocatalytic Activity

Nanomaterials ◽  
2019 ◽  
Vol 9 (6) ◽  
pp. 883 ◽  
Author(s):  
Yang Xiao ◽  
Shihao Chen ◽  
Yinhai Wang ◽  
Zhengfa Hu ◽  
Hui Zhao ◽  
...  
Keyword(s):  
Photocatalytic Activity ◽  
Oxygen Vacancies ◽  
Photocatalytic Performance ◽  
Localized States ◽  
Photoelectron Spectra ◽  
Infrared Light ◽  
Universal Method ◽  
High Concentration ◽  
Simple Method ◽  
X Ray

Modification of the surface properties of SrTiO3 crystals by regulating the reaction environment in order to improve the photocatalytic activity has been widely studied. However, the development of a facile, effective, and universal method to improve the photocatalytic activity of these crystals remains an enormous challenge. We have developed a simple method to modify the surface environment of SrTiO3 by ethanol quenching, which results in enhanced UV, visible and infrared light absorption and photocatalytic performance. The SrTiO3 nanocrystals were preheated to 800 °C and immediately quenched by submersion in ethanol. X-ray diffraction patterns, electron paramagnetic resonance spectra, and X-ray photoelectron spectra indicated that upon rapid ethanol quenching, the interaction between hot SrTiO3 and ethanol led to the introduction of a high concentration of oxygen vacancies on the surface of the SrTiO3 lattice. Consequently, to maintain the regional charge balance of SrTiO3, Sr2+ could be substituted for Ti4+. Moreover, oxygen vacancies induced localized states into the band gap of the modified SrTiO3 and acted as photoinduced charge traps, thus promoting the photocatalytic activity. The improved photocatalytic performance of the modified SrTiO3 was demonstrated by using it for the decomposition of rhodamine B and production of H2 from water under visible or solar light.

Preparation of Heterojunction Semiconductor SnS2/SnO2 with Enhanced Photocatalytic Properties

2013 ◽  
Vol 316-317 ◽  
pp. 1059-1062 ◽  
Author(s):  
Ping Chen ◽  
Ming Sheng Qin ◽  
Fu Qiang Huang
Keyword(s):  
Photocatalytic Activity ◽  
Single Phase ◽  
Near Infrared ◽  
Photocatalytic Performance ◽  
Chemical Compositions ◽  
X Ray Diffraction ◽  
Simple Method ◽  
X Ray ◽  
Structure Morphology ◽  
Nir Absorption

The Formation of Heterojunction Structure between Two Semiconductors Was Considered as an Effective Method to Enhance the Photocatalytic Activity. here, we Reported a Simple Method to Prepare SnS2/SnO2Heterojunction Photocatalysts by Annealing SnS2in Air. the Structure, Morphology, Chemical Compositions and Optical Properties of the Obtained Materials Were Characterized by the X-ray Diffraction (XRD), Scanning Electron Microscope (SEM), Energy-dispersive X-ray Spectroscopy (EDX) and Ultraviolet-visible-near Infrared (UV-Vis-NIR) Absorption Spectra. the Photocatalytic Investigations Showed the Composites Have Higher Photocatalytic Activity than the Single-phase SnS2. the SnS2Powder which Annealed at 400 °C for 60 Min Showed the Highest Photocatalytic Performance.

scholarly journals Study of the Effect of TiO2 Layer on the Adsorption and Photocatalytic Activity of TiO2-MoS2 Heterostructures under Visible-Infrared Light

2020 ◽  
Vol 2020 ◽  
pp. 1-9 ◽  
Author(s):  
N. Cruz-González ◽  
O. Calzadilla ◽  
J. Roque ◽  
F. Chalé-Lara ◽  
J. K. Olarte ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Photocatalytic Activity ◽  
Photoelectron Spectroscopy ◽  
Diffuse Reflectance Spectroscopy ◽  
Nitrogen Adsorption ◽  
High Photocatalytic Activity ◽  
Infrared Light ◽  
Polluted Water ◽  
Light Spectrum ◽  
X Ray

In the last decade, the urgent need to environmental protection has promoted the development of new materials with potential applications to remediate air and polluted water. In this work, the effect of the TiO2 thin layer over MoS2 material in photocatalytic activity is reported. We prepared different heterostructures, using a combination of electrospinning, solvothermal, and spin-coating techniques. The properties of the samples were analyzed by scanning electron microscopy (SEM), transmission electron microscopy (TEM), atomic force microscopy (AFM), X-ray diffraction (XRD), nitrogen adsorption-desorption isotherms, UV-Vis diffuse reflectance spectroscopy (UV-Vis-DRS), and X-ray photoelectron spectroscopy (XPS). The adsorption and photocatalytic activity were evaluated by discoloration of rhodamine B solution. The TiO2-MoS2/TiO2 heterostructure presented three optical absorption edges at 1.3 eV, 2.28 eV, and 3.23 eV. The high adsorption capacity of MoS2 was eliminated with the addition of TiO2 thin film. The samples show high photocatalytic activity in the visible-IR light spectrum.

Preparation of Visible-Light-Responsive TiO2-xNx Photocatalyst by a Very Simple Method

2011 ◽  
Vol 383-390 ◽  
pp. 3188-3191
Author(s):  
Han Jie Huang ◽  
Wen Long She ◽  
Ling Wen Yang ◽  
Hai Peng Huang
Keyword(s):  
Photocatalytic Activity ◽  
Visible Light ◽  
Photoelectron Spectroscopy ◽  
Diffuse Reflection ◽  
Ammonia Solution ◽  
Reflection Spectra ◽  
X Ray Diffraction ◽  
Simple Method ◽  
X Ray ◽  
Light Excitation

A visible-light-responsive TiO2-xNx photocatalyst was prepared by a very simple method. Ammonia solution was used as nitrogen resource in this paper. The TiO2-xNx photocatalyst was characterized by X-ray diffraction (XRD), Brunauer-Emmett-Teller (BET), UV-Vis diffuse reflection spectra (DRS), and X-ray photoelectron spectroscopy (XPS). The ethylene was selected as a target pollutant under visible light excitation to evaluate the activity of this photocatalyst. The new prepared TiO2-xNx photocatalyst with strong photocatalytic activity under visible light irradiation was demonstrated in the experiment.

scholarly journals Hydrothermal Synthesis of Iodine-Doped Nanoplates with Enhanced Visible and Ultraviolet-Induced Photocatalytic Activities

2012 ◽  
Vol 2012 ◽  
pp. 1-12 ◽  
Author(s):  
Jiang Zhang ◽  
Zheng-Hong Huang ◽  
Yong Xu ◽  
Feiyu Kang
Keyword(s):  
Photocatalytic Activity ◽  
Photoelectron Spectroscopy ◽  
Oxygen Vacancies ◽  
Diffuse Reflectance Spectroscopy ◽  
Synergetic Effect ◽  
X Ray Diffraction ◽  
X Ray ◽  
Selected Area Electron Diffraction ◽  
Transmission Electron ◽  
Photocatalytic Activities

The iodine-doped Bi2WO6(I-BWO) photocatalyst was prepared via a hydrothermal method using potassium iodide as the source of iodine. The samples were characterized by X-ray diffraction (XRD), scanning electron microscope (SEM), transmission electron microscopy (TEM) and selected area electron diffraction (SAED), X-ray photoelectron spectroscopy (XPS), UV-vis diffuse reflectance spectroscopy (DRS), and photoluminescence (PL) spectroscopy. The photocatalytic activity of I-BWO for the degradation of rhodamine B (RhB) was higher than that of pure BWO and I2-BWO regardless of visible light (>420 nm) or ultraviolet light (<400 nm) irradiation. The results of DRS analysis showed that the I-BWO and I2-BWO catalysts had narrower band gaps. XPS analysis proved that the multivalent iodine species including I0and were coadsorbed on the defect surface of Bi2WO6in I-BWO. The enhanced PL intensity revealed that a large number of defects of oxygen vacancies were formed by the doping of iodine. The enhanced photocatalytic activity of I-BWO for degradation of RhB was caused by the synergetic effect of a small crystalline size, a narrow band gap, and plenty of oxygen vacancies.

scholarly journals Synthesis and Photocatalytic Activity of Mo-Doped TiO2Nanoparticles

2015 ◽  
Vol 2015 ◽  
pp. 1-8 ◽  
Author(s):  
Ji-guo Huang ◽  
Xue-ting Guo ◽  
Bo Wang ◽  
Lin-yang Li ◽  
Mei-xia Zhao ◽  
...  
Keyword(s):  
Methylene Blue ◽  
Photocatalytic Activity ◽  
Crystallite Size ◽  
Lattice Distortion ◽  
Visible Region ◽  
Photoelectron Spectra ◽  
Solar Light ◽  
Xenon Lamp ◽  
X Ray ◽  
Mo Doping

The undoped and Mo-doped TiO2nanoparticles were synthesized by sol-gel method. The as-prepared samples were characterized by X-ray diffraction (XRD), diffuse reflectance UV-visible absorption spectra (UV-vis DRS), X-ray photoelectron spectra (XPS), and transmission electron microscopy (TEM). The photocatalytic activity was evaluated by photocatalytic degradation of methylene blue under irradiation of a 500 W xenon lamp and natural solar light outdoor. Effects of calcination temperatures and Mo doping amounts on crystal phase, crystallite size, lattice distortion, and optical properties were investigated. The results showed that most of Mo6+took the place of Ti4+in the crystal lattice of TiO2, which inhibited the growth of crystallite size, suppressed the transformation from anatase to rutile, and led to lattice distortion of TiO2. Mo doping narrowed the band gap (from 3.05 eV of TiO2to 2.73 eV of TiMo0.02O) and efficiently increased the optical absorption in visible region. Mo doping was shown to be an efficient method for degradation of methylene blue under visible light, especially under solar light. When the calcination temperature was 550°C and the Mo doping amount was 2.0%, the Mo-doped TiO2sample exhibited the highest photocatalytic activity.

scholarly journals Rapid preparation of terbium-doped titanium dioxide nanoparticles and their enhanced photocatalytic performance

2019 ◽  
Vol 6 (10) ◽  
pp. 191077 ◽  
Author(s):  
Zhencui Wang ◽  
Yuechao Song ◽  
Xingfei Cai ◽  
Jun Zhang ◽  
Tianle Tang ◽  
...  
Keyword(s):  
Titanium Dioxide ◽  
Photocatalytic Activity ◽  
Photocatalytic Performance ◽  
Diffuse Reflectance Spectroscopy ◽  
Titanium Dioxide Nanoparticles ◽  
Earth Metal ◽  
Nitrate Hexahydrate ◽  
Doping Amount ◽  
X Ray ◽  
Low Toxicity

Further applications of photocatalysis were limited by the high recombination probability of photo-induced electron–hole pairs in traditional titanium dioxide nanoparticles (TiO 2 NPs). Herein, we modified them with rare earth metal via a facile sol–gel method, using tetrabutyl titanate as a precursor and terbium (III) nitrate hexahydrate as terbium (Tb) source. The resulting samples with different Tb doping amounts (from 0 to 2%) have been characterized by X-ray diffraction, UV–visible diffuse reflectance spectroscopy, X-ray photo-electron spectroscopy and a scanning electron microscope. The photocatalytic performance of Tb-doped TiO 2 was evaluated by the degradation of methylene blue. The effects of Tb doping amount and initial pH value of solution were investigated in detail. The composite with Tb doping amount of 1.0 wt% showed the highest photocatalytic performance. It exhibited approximately three times enhancement in photocatalytic activity with a reaction rate constant of 0.2314 h −1 when compared with that of commercial P25 (0.0827 h −1 ). In addition, it presented low toxicity on zebrafishes with 96 h-LC 50 of 23.2 mg l −1 , and has been proved to be reusable for at least four cycles without significant loss of photocatalytic activity. A probable photocatalytic mechanism of Tb-doped TiO 2 was proposed according to the active species trapping experiments. The high photocatalytic performance, excellent reusability and low toxicity of Tb-doped TiO 2 indicated that it is a promising candidate material in the future treatment of dye wastewater.

scholarly journals Oxygen Vacancy Enhanced Photoreduction Cr(VI) on Few-Layers BiOBr Nanosheets

Catalysts ◽  
2019 ◽  
Vol 9 (6) ◽  
pp. 558 ◽  
Author(s):  
Yin Peng ◽  
Pengfei Kan ◽  
Qian Zhang ◽  
Yinghua Zhou
Keyword(s):  
Oxygen Vacancies ◽  
Surface Defect ◽  
Photocatalytic Performance ◽  
Electrochemical Impedance ◽  
Light Irradiation ◽  
Solvothermal Reaction ◽  
Defect Engineering ◽  
High Concentration ◽  
Solar Light Irradiation ◽  
2D Nanomaterials

2D nanomaterials, with unique structural and electronic features, had been demonstrated as excellent photocatalysts, whose catalytic properties could be tunable with surface defect engineering. In this work, few-layer BiOBr nanosheets with oxygen vacancies (BiOBr-Ov) have been fabricated by a simple solvothermal reaction with the help of ethylene glycol. The obtained BiOBr-Ov exhibited the superior photocatalytic performance with a complete reduction of Cr(VI) (20 mg/L) within 12 min by visible light irradiation. Moreover, Cr(VI) with a high concentration (such as 30 mg/L) only requires 2 min to be photoreduced completely under solar light irradiation. The enhanced photocatalytic performance is contributed to the existence of oxygen vacancies. It has been proved by the results of electrochemical impedance and photocurrent that oxygen vacancies can effectively suppress recombination of photogenerated carriers.

scholarly journals Photocatalytic Performance of SiO2/CNOs/TiO2 to Accelerate the Degradation of Rhodamine B under Visible Light

Nanomaterials ◽  
2019 ◽  
Vol 9 (12) ◽  
pp. 1671 ◽  
Author(s):  
Weike Zhang ◽  
Yanrong Zhang ◽  
Kai Yang ◽  
Yanqing Yang ◽  
Jia Jia ◽  
...  
Keyword(s):  
Photocatalytic Activity ◽  
Visible Light ◽  
Rhodamine B ◽  
Photoelectron Spectroscopy ◽  
Degradation Rate ◽  
Photocatalytic Performance ◽  
Sol Gel ◽  
X Ray Diffraction ◽  
X Ray ◽  
Electronic Microscope

A silicon dioxide/carbon nano onions/titanium dioxide (SiO2/CNOs/TiO2) composite was synthesized by a simple sol-gel method and characterized by the methods of X-ray diffraction (XRD), scanning electronic microscope (SEM), X-ray photoelectron spectroscopy (XPS), Brunauer–Emmett–Teller (BET), Fourier transform infrared (FTIR), thermogravimetric analysis (TG), differential scanning calorimeter (DSC) and UV-Vis diffuse reflectance spectra (UV-Vis DRS). In this work, the photocatalytic activity of the SiO2/CNOs/TiO2 photocatalyst was assessed by testing the degradation rate of Rhodamine B (RhB) under visible light. The results indicated that the samples exhibited the best photocatalytic activity when the composite consisted of 3% CNOs and the optimum dosage of SiO2/CNOs/TiO2(3%) was 1.5 g/L as evidenced by the highest RhB degradation rate (96%). The SiO2/CNOs/TiO2 composite greatly improved the quantum efficiency of TiO2. This work provides a new option for the modification of subsequent nanocomposite oxide nanoparticles.

scholarly journals Improvement of Photocatalytic Performance for the g-C3N4/MoS2 Composite Used for Hypophosphite Oxidation

2020 ◽  
Vol 2020 ◽  
pp. 1-9
Author(s):  
Wei Guan ◽  
Kuang He ◽  
Jianwei Du ◽  
Yong Wen ◽  
Mingshan Li ◽  
...  
Keyword(s):  
Photocatalytic Performance ◽  
High Efficiency ◽  
Emission Spectra ◽  
Chelating Agent ◽  
Photoelectron Spectra ◽  
X Ray Diffraction ◽  
Response Measurement ◽  
X Ray ◽  
Transient Photocurrent ◽  
Oxidation Efficiency

The synthesized g-C3N4/MoS2 composite was a high-efficiency photocatalytic for hypophosphite oxidation. In this work, a stable and cheap g-C3N4 worked as the chelating agent and combined with the MoS2 materials. The structures of the fabricated g-C3N4/MoS2 photocatalyst were characterized by some methods including X-ray diffraction (XRD), scanning electron microscopy (SEM), and X-ray photoelectron spectra (XPS). Moreover, the photocatalytic performances of various photocatalysts were measured by analyzing the oxidation efficiency of hypophosphite under visible light irradiation and the oxidation efficiency of hypophosphite using the g-C3N4/MoS2 photocatalyst which was 93.45%. According to the results, the g-C3N4/MoS2 composite showed a promising photocatalytic performance for hypophosphite oxidation. The improved photocatalytic performance for hypophosphite oxidation was due to the effective charge separation analyzed by the photoluminescence (PL) emission spectra. The transient photocurrent response measurement indicated that the g-C3N4/MoS2 composites (2.5 μA cm–2) were 10 times improved photocurrent intensity and 2 times improved photocurrent intensity comparing with the pure g-C3N4 (0.25 μA cm–2) and MoS2 (1.25 μA cm–2), respectively. The photocatalytic mechanism of hypophosphite oxidation was analyzed by adding some scavengers, and the recycle experiments indicated that the g-C3N4/MoS2 composite had a good stability.

Sign in / Sign up

Export Citation Format

Share Document