scholarly journals TiO2 Modification with Transition Metallic Species (Cr, Co, Ni, and Cu) for Photocatalytic Abatement of Acetic Acid in Liquid Phase and Propene in Gas Phase

Materials ◽  
2018 ◽  
Vol 12 (1) ◽  
pp. 40 ◽  
Author(s):  
Ana Amorós-Pérez ◽  
Laura Cano-Casanova ◽  
Ana Castillo-Deltell ◽  
María Lillo-Ródenas ◽  
María Román-Martínez
Keyword(s):  
Acetic Acid ◽  
Gas Phase ◽  
Photoelectron Spectroscopy ◽  
Diffuse Reflectance Spectroscopy ◽  
X Ray Diffraction ◽  
X Ray ◽  
Phase Oxidation ◽  
Gas Phase Oxidation ◽  
Species Being ◽  
Metallic Species

The commercial P25 titania has been modified with transition metallic species (Cr, Co, Ni, and Cu), added by impregnation with aqueous solutions of the corresponding nitrates. The preparation procedure also includes a heat treatment (500 °C) in argon to decompose the nitrates, remove impurities and to strengthen the metal–TiO2 interaction. The catalysts have been thoroughly characterized using N2 adsorption, scanning electron microscopy (SEM), X-ray diffraction (XRD), UV-visible diffuse-reflectance spectroscopy (UV-vis DRS) and X-ray photoelectron spectroscopy (XPS), and have been tested in the aqueous phase decomposition of acetic acid and in the gas phase oxidation of propene, using an irradiation source of 365 nm in both cases. The photocatalytic activity of the four metal-containing catalysts varies with the nature of the metallic species and follows a similar trend in the two tested reactions. The effect of the nature of the added metallic species is mainly based on the electrochemical properties of the supported species, being Cu/P25 (the sample that contains copper) the best performing catalyst. In the photodecomposition of acetic acid, all the metal-containing samples are more active than bare P25, while in the gas phase oxidation of propene, bare P25 is more active. This has been explained considering that the rate-determining steps are different in gas and liquid media.

scholarly journals Solid-Gas Phase Photo-Catalytic Behaviour of Rutile and TiOn (1 < n < 2) Sub-Oxide Phases for Self-Cleaning Applications

Materials ◽  
2019 ◽  
Vol 12 (1) ◽  
pp. 170 ◽  
Author(s):  
Manuel Nuño ◽  
Vaia Adamaki ◽  
David M. Tobaldi ◽  
Maria J. Hortigüela Gallo ◽  
Gonzalo Otero-Irurueta ◽  
...  
Keyword(s):  
Gas Phase ◽  
Photoelectron Spectroscopy ◽  
Diffuse Reflectance Spectroscopy ◽  
Catalytic Performance ◽  
Thermal Reduction ◽  
X Ray Diffraction ◽  
X Ray ◽  
Electrical Conductivities ◽  
Oxide Phases ◽  
Self Cleaning

The solid-gas phase photo-catalytic activities of rutile TiO2 and TiOn (1 < n < 2) sub-oxide phases have been evaluated. Varying concentrations of Ti3+ defects were introduced into the rutile polymorph of titanium dioxide through carbo-thermal reduction at temperatures ranging from 350 °C to 1300 °C. The resulting sub-oxides formed were characterized by X-ray diffraction, X-ray photoelectron spectroscopy, scanning electron microscopy, impedance spectroscopy and UV-visible diffuse reflectance spectroscopy. The presence of Ti3+ in rutile exposed to high reduction temperatures was confirmed by X-ray diffraction. In addition, a Ti3+-Ti4+ system was demonstrated to enhance the photo-catalytic properties of rutile for the degradation of the air pollutants NO2 and CO2 under UV irradiation of wavelengths (λ) 376–387 nm and 381–392 nm. The optimum reduction temperature for photo-catalytic activity was within the range 350–400 °C and attributed to improved charge-separation. The materials that were subject to carbo-thermal reduction at temperatures of 350 °C and 400 °C exhibited electrical conductivities over one hundred times higher compared to the non-reduced rutile. The results highlight that sub-oxide phases form an important alternative approach to doping with other elements to improve the photo-catalytic performance of TiO2. Such materials are important for applications such as self-cleaning where particles can be incorporated into surface coatings.

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, Characterization, and Photocatalytic Evaluation of Manganese (III) Phthalocyanine Sensitized ZnWO4 (ZnWO4MnPc) for Bisphenol A Degradation under UV Irradiation

Nanomaterials ◽  
2020 ◽  
Vol 10 (11) ◽  
pp. 2139 ◽  
Author(s):  
Chukwuka Bethel Anucha ◽  
Ilknur Altin ◽  
Zekeriya Biyiklioglu ◽  
Emin Bacaksiz ◽  
Ismail Polat ◽  
...  
Keyword(s):  
Bisphenol A ◽  
Uv Irradiation ◽  
Photoelectron Spectroscopy ◽  
Photocatalytic Performance ◽  
Diffuse Reflectance Spectroscopy ◽  
Degradation Process ◽  
X Ray Diffraction ◽  
X Ray ◽  
Uv Visible ◽  
Adsorption Desorption

ZnWO4MnPc was synthesized via a hydrothermal autoclave method with 1 wt.% manganese (iii) phthalocyanine content. The material was characterized for its structural and morphological features via X-ray diffraction (XRD) spectroscopy, Fourier transform infrared (FTIR) spectroscopy, transmission emission microscopy (TEM), scanning electron microscopy-Energy dispersive X-ray spectroscopy (SEM-EDX), N2 adsorption–desorption at 77K, X-ray photoelectron spectroscopy (XPS), and UV-visible/diffuse reflectance spectroscopy(UV-vis/DRS). ZnWO4MnPc photocatalytic performance was tested on the degradation of bisphenol A (BPA). The ZnWO4MnPc material removed 60% of BPA after 4 h of 365 nm UV irradiation. Degradation process improved significantly to about 80% removal in the presence of added 5 mM H2O2 after 4 h irradiation. Almost 100% removal was achieved after 30 min under 450 nm visible light irradiation in the presence of same concentration of H2O2. The effect of ions and humic acid (HA) towards BPA removal was also investigated.

scholarly journals Impact of Preparative pH on the Morphology and Photocatalytic Activity of BiVO4

2012 ◽  
Vol 2012 ◽  
pp. 1-7 ◽  
Author(s):  
Yongbiao Wan ◽  
Sihong Wang ◽  
Wenhao Luo ◽  
Lianhua Zhao
Keyword(s):  
Photocatalytic Activity ◽  
Photoelectron Spectroscopy ◽  
Diffuse Reflectance Spectroscopy ◽  
Ammonia Solution ◽  
Synthesis Process ◽  
X Ray Diffraction ◽  
X Ray ◽  
Blue Solution ◽  
Absorption Performance ◽  
The Impact

Adjusting pH with an ammonia solution during the synthesis, single-crystalline BiVO4has been prepared using Bi(NO3)3·5H2O and NH4VO3as starting materials through aqueous-phase precipitation at room temperature. The prepared samples are characterized by X-ray diffraction (XRD), diffuse reflectance spectroscopy (DRS), X-ray photoelectron spectroscopy (XPS), and scanning electron microscope (SEM). The impact of pH on structure, surface morphology, visible-light photocatalytic activity, and light absorption performance of BiVO4is explored and discussed. During the synthesis process, neither extremely acidic (low pH) nor basic (high pH) conditions are desirable for the formation of BiVO4in monoclinic phase. The highest photocatalytic performance on the degradation of a methylene blue solution is observed under pH=7.0for BiVO4in monoclinic scheelite, which is attributed to its small grain size and marked surface oxygen evolution ability.

scholarly journals The nature and effects of rhodium and antimony dopants on the electronic structure of TiO2: towards design of Z-scheme photocatalysts

2016 ◽  
Vol 4 (18) ◽  
pp. 6946-6954 ◽  
Author(s):  
E. N. K. Glover ◽  
S. G. Ellington ◽  
G. Sankar ◽  
R. G. Palgrave
Keyword(s):  
Fine Structure ◽  
Photoelectron Spectroscopy ◽  
Diffuse Reflectance ◽  
Diffuse Reflectance Spectroscopy ◽  
Reflectance Spectroscopy ◽  
X Ray Diffraction ◽  
Edge Structure ◽  
X Ray ◽  
Antimony Doping ◽  
X Ray Absorption

The nature and effects of rhodium and antimony doping in TiO2 have been investigated using X-ray diffraction (XRD), X-ray Photoelectron Spectroscopy (XPS), Extended X-ray Absorption Fine Structure (EXAFS), X-ray Absorption Near Edge Structure (XANES) and diffuse reflectance spectroscopy.

scholarly journals Effect of reaction parameters on WOx nanostructures by the solvothermal process

2021 ◽  
Vol 4 (3) ◽  
pp. 234-244
Author(s):  
Amelia Olivas Sarabia ◽  
Marlene N Cardoza-Contreras ◽  
Gonzalo Lastra Medina ◽  
Marcos Alan Cota Leal ◽  
Selene Sepúlveda Guzmán
Keyword(s):  
Acetic Acid ◽  
Reaction Time ◽  
Photoelectron Spectroscopy ◽  
Solvothermal Method ◽  
Ultra Violet ◽  
Oxidation States ◽  
X Ray Diffraction ◽  
Reaction Parameters ◽  
X Ray ◽  
Xrd Patterns

In this work, nanowires and nanorods of WOx have been synthesized by the solvothermal method. The effect of reaction time and acetic acid as solvent were studied. X-ray diffraction (XRD) patterns showed the monoclinic WO2.72, WO2.79, and orthorhombic WO3 crystalline structures. Scanning Electron Microscopy (SEM) and High-Resolution Transmission Electronic Microscopy (HRTEM) images presented nanostructures such as nanowires and nanorods at different sizes. Band gap energies were supplied by Ultra Violet visible (UV-vis) absorption spectra. The Photoluminescence (PL) spectra exhibited three emission peaks in the blue zone at 440, 460, and 484 nm. X-ray Photoelectron Spectroscopy (XPS) was used to calculate W6+, W5+, and W4+ oxidation states. The results showed that increasing the reaction time from 10 h to 24 h affected the crystalline structure from monoclinic to orthorhombic. Moreover, with the addition of acetic acid as solvent, the crystal structure is not affected but stabilizes the monoclinic phase in the course of time.

scholarly journals Photoactivity of Titanium Dioxide Foams

2018 ◽  
Vol 2018 ◽  
pp. 1-9
Author(s):  
Maryam Jami ◽  
Ralf Dillert ◽  
Yanpeng Suo ◽  
Detlef W. Bahnemann ◽  
Michael Wark
Keyword(s):  
Gas Phase ◽  
Photoelectron Spectroscopy ◽  
Colloidal Suspensions ◽  
Air Purification ◽  
Semiconductor Materials ◽  
X Ray Diffraction ◽  
X Ray ◽  
Mechanical Stirring ◽  
Amphiphilic Molecules ◽  
Oxidation Of No

TiO2 foams have been prepared by a simple mechanical stirring method. Short-chain amphiphilic molecules have been used to stabilize colloidal suspensions of TiO2 nanoparticles. TiO2 foams were characterized by X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), UV-vis absorption spectroscopy, and scanning electron microscopy (SEM). The photoassisted oxidation of NO in the gas phase according to ISO 22197-1 has been used to compare the photoactivity of the newly prepared TiO2 foams to that of the original powders. The results showed that the photoactivity is increased up to about 135%. Foam structures seem to be a good means of improving the photoactivity of semiconductor materials and can readily be used for applications such as air purification devices.

scholarly journals Design of Defect and Metallic Silver in Silver Phosphate Photocatalyst Using the Hydroxyapatite and Glucose

2020 ◽  
Vol 20 (6) ◽  
pp. 1441
Author(s):  
Uyi Sulaeman ◽  
Suhendar Suhendar ◽  
Hartiwi Diastuti ◽  
Roy Andreas ◽  
Shu Yin
Keyword(s):  
Photoelectron Spectroscopy ◽  
Diffuse Reflectance ◽  
Diffuse Reflectance Spectroscopy ◽  
Glucose Solution ◽  
Reflectance Spectroscopy ◽  
Metallic Silver ◽  
X Ray Diffraction ◽  
X Ray ◽  
Silver Phosphate ◽  
Agno3 Aqueous Solution

The defect and metallic silver (Ag) in silver phosphate (Ag3PO4) photocatalyst were successfully generated using hydroxyapatite (HA) and glucose. Two steps of synthesis were done in these experiments. Firstly, the Ag/HA powder was prepared by reacting AgNO3 and HA, followed by the addition of a glucose solution. Secondly, the suspension of Ag/HA was reacted with AgNO3 aqueous solution. The yellow product of Ag/Ag3PO4 photocatalyst was produced. The products were characterized using X-Ray Diffraction (XRD), Diffuse Reflectance Spectroscopy (DRS), Scanning Electron Microscope (SEM), Brunauer–Emmett–Teller (BET) and X-ray Photoelectron Spectroscopy (XPS). The decreased ratio of O/Ag and metallic Ag formation observed by the XPS was detected as the possible defect and Ag-doping in the photocatalyst. The enhanced photocatalytic activity might be caused by the oxygen vacancy and metallic Ag in Ag3PO4 that enables the separation of photo-generated electrons and holes.

Synthesis and Photocatalytic Activity of Fluorine DOPED-g-C3N4

2019 ◽  
Vol 889 ◽  
pp. 24-32 ◽  
Author(s):  
Nguyen Van Phuc ◽  
Doan Tran An ◽  
Nguyen Ngoc Tri ◽  
Tran Huu Ha ◽  
Tran Thi Thu Hien ◽  
...  
Keyword(s):  
Photoelectron Spectroscopy ◽  
Carbon Nitride ◽  
Diffuse Reflectance ◽  
Dft Calculation ◽  
Diffuse Reflectance Spectroscopy ◽  
Weight Ratio ◽  
Ammonium Fluoride ◽  
X Ray Diffraction ◽  
Photo Degradation ◽  
X Ray

F-doped graphitic carbon nitride was synthesized via simple solid-state calcination of mixture with various weight ratios of urea, as precursor, and ammonium fluoride, as modifying agent. The obtained materials were characterized by a number of modern methods such as X-ray diffraction, Scanning electron microscopy, Infrared spectroscopy, Ultraviolet-visible diffuse reflectance spectroscopy, Thermo-gravimetry analysis, X-ray photoelectron spectroscopy, which all demonstrated the successful modification of g-C3N4 by fluorine. The experimental results illustrated that the doped sample, in which weight ratio of urea and ammonium fluoride equals 93:7 respectively, performs the highest photo-degradation efficiency of Rhodamine B up to 75 % after 7-hour visible light irradiation. The doping effect of fluorine on photo-catalytic activity of g-C3N4 was also discussed within supporting information of DFT calculation.

Facile deposition of carbon-doped TiO2 films by two-electrode electrodeposition setup

2021 ◽  
pp. 2150175
Author(s):  
Necati Basman ◽  
Mehmet Gokcen
Keyword(s):  
Photoelectron Spectroscopy ◽  
Diffuse Reflectance Spectroscopy ◽  
Carbon Doping ◽  
Silicon Substrates ◽  
X Ray Diffraction ◽  
High Carbon ◽  
X Ray ◽  
Carbon Doped ◽  
Surface Areas ◽  
Uv Visible

This study presents a simple electrochemical deposition route to obtain carbon-doped TiO2 films. The deposition of the films is carried out on silicon substrates from a mixture of methanol (CH3OH) and Titanium (IV) isopropoxide (Ti[OCH(CH3)2]4) solution using a simple two-electrode electrodeposition setup. The obtained films are characterized by scanning electron microscopy (SEM), X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), UV-Visible diffuse reflectance spectroscopy (DRS) and conductivity measurements. Depending on the deposition conditions, both amorphous and crystalline TiO2 films could be obtained. It is found that carbon is doped both substitutionally and interstitially. High carbon doping (up to 18.96%) enables to obtain TiO2 film with narrowed bandgap and high conductivity to about 2.3 eV and [Formula: see text] S cm[Formula: see text], respectively. This study suggests that the proposed electrodeposition route offers an easy way of obtaining conductive and narrowed bandgap TiO2 films on large surface areas.

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