scholarly journals Effect of the Microstructure of the Semiconductor Support on the Photocatalytic Performance of the Pt-PtOx/TiO2 Catalyst System

Materials ◽  
2021 ◽  
Vol 14 (4) ◽  
pp. 943
Author(s):  
Katalin Majrik ◽  
Zoltán Pászti ◽  
László Korecz ◽  
Judith Mihály ◽  
Zoltán May ◽  
...  
Keyword(s):  
Photoelectron Spectroscopy ◽  
Photocatalytic Performance ◽  
Sol Gel ◽  
Catalyst System ◽  
Structural Features ◽  
H2 Production ◽  
X Ray ◽  
Preparation Conditions ◽  
Different Temperatures ◽  
Sol Gel Synthesis

The influence of the semiconductor microstructure on the photocatalytic behavior of Pt-PtOx/TiO2 catalysts was studied by comparing the methanol-reforming performance of systems based on commercial P25 or TiO2 from sol–gel synthesis calcined at different temperatures. The Pt co-catalyst was deposited by incipient wetness and formed either by calcination or high-temperature H2 treatment. Structural features of the photocatalysts were established by X-ray powder diffraction (XRD), electron spin resonance (ESR), X-ray photoelectron spectroscopy (XPS), optical absorption, Raman spectroscopy and TEM measurements. In situ reduction of Pt during the photocatalytic reaction was generally observed. The P25-based samples showed the best H2 production, while the activity of all sol–gel-based samples was similar in spite of the varying microstructures resulting from the different preparation conditions. Accordingly, the sol–gel-based TiO2 has a fundamental structural feature interfering with its photocatalytic performance, which could not be improved by annealing in the 400–500 °C range even by scarifying specific surface area at higher temperatures.

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.

Sol–gel synthesis, X-ray photoelectron spectroscopy and electrical conductivity of Co-doped (La, Sr)(Ga, Mg)O3−δ perovskites

2007 ◽  
Vol 27 (13-15) ◽  
pp. 4291-4296 ◽  
Author(s):  
Riccardo Polini ◽  
Alessia Falsetti ◽  
Enrico Traversa ◽  
Oliver Schäf ◽  
Philippe Knauth
Keyword(s):  
Electrical Conductivity ◽  
Photoelectron Spectroscopy ◽  
Sol Gel ◽  
X Ray ◽  
Sol Gel Synthesis ◽  
Co Doped

scholarly journals Construction of Direct Z-Scheme Photocatalyst by Mg1.2Ti1.8O5 and g-C3N4 Nanosheets toward Photocatalytic H2 Production and Disinfection

2019 ◽  
Vol 2019 ◽  
pp. 1-9
Author(s):  
Sijia Gu ◽  
Dan Zhang ◽  
Shirong Luo ◽  
Heng Yang
Keyword(s):  
Escherichia Coli ◽  
Photocatalytic Performance ◽  
Diffuse Reflectance Spectroscopy ◽  
Sol Gel ◽  
H2 Production ◽  
X Ray ◽  
E Coli ◽  
Carrier Separation ◽  
Positive Valence ◽  
Calcination Method

Exploring a novel and efficient photocatalyst is the key research goal to relieve energy and environmental issues. Herein, Z-scheme heterojunction composites were successfully fabricated by loading g-C3N4 nanosheets (CN) on the surface of Mg1.2Ti1.8O5 nanoflakes (MT) through a simple sol-gel method followed by the calcination method. The crystalline phase, morphologies, specific surface area, and optical and electrochemical performance of the samples were characterized by X-ray diffraction (XRD), field emission scanning electron microscopy (FE-SEM), energy-disperse X-ray spectroscopy (EDS), Brunauer-Emmett-Teller (BET), diffuse reflectance spectroscopy (DRS), and electrochemical measurements. Considering the suitable band structures of the components, the photocatalytic performance was evaluated by photocatalytic H2O splitting and photocatalytic inactivation of Escherichia coli (E. coli). Among the samples, MT/CN-10 (the molar percentage of melamine to as-obtained Mg-Ti gel was 10%) shows superior photocatalytic performance, which the average H2 production rate was 3.57 and 7.24 times higher than those of MT and CN alone. Additionally, the efficiency of inactivating Escherichia coli (E. coli) over MT/CN-10 was 1.95 and 2.06 times higher as compared to pure MT and CN, respectively. The enhancement of the photocatalytic performance was attributed to the advantages of the extremely negative conduction band (CB) of CN and the extremely positive valence band (VB) of MT, the enhanced light absorption, and more efficient photogenerated charge carrier separation.

Study of Pseudoboehmite Synthesis by Sol-Gel Process

2006 ◽  
Vol 45 ◽  
pp. 260-265 ◽  
Author(s):  
Antônio Hortêncio Munhoz Jr. ◽  
Leila Figueiredo de Miranda ◽  
G.N. Uehara
Keyword(s):  
Sol Gel ◽  
Thermo Gravimetric Analysis ◽  
Ammonium Hydroxide ◽  
Gravimetric Analysis ◽  
X Ray Diffraction ◽  
Scanning Calorimetry ◽  
X Ray ◽  
Sol Gel Process ◽  
Different Temperatures ◽  
Sol Gel Synthesis

A pseudoboehmite was obtained by sol-gel synthesis using aluminum nitrate as precursor. It was used a 2n full factorial design for studying the effect of the temperature of synthesis, the concentration of ammonium hydroxide, and the radiation dose in the product of sol-gel synthesis. The product of the synthesis was analyzed by scanning electron microscopy, x-ray diffraction of the product (after firing the pseudoboehmite at different temperatures), and it was also analyzed the temperature of endothermic and exothermic transformations using the thermo gravimetric analysis (TG) and differential scanning calorimetry (DSC). The X-ray diffraction data show that α-alumina was obtained at 1100o C.

Preparation and Characterization of TiO2 Nanoparticle with SiO2 Shell

2011 ◽  
Vol 233-235 ◽  
pp. 1188-1191
Author(s):  
Hong Cai ◽  
Yan Chen ◽  
Yun Ying Wu
Keyword(s):  
Photoelectron Spectroscopy ◽  
Photocatalytic Performance ◽  
Sol Gel ◽  
Chemical Components ◽  
X Ray Diffraction ◽  
X Ray ◽  
Ft Ir ◽  
Bonding Phase ◽  
Hydrolysis Of

Nano-TiO2 particles were prepared by sol-gel method, of which the surfaces were coated by SiO2. The coating was achieved by the hydrolysis of sodium silicate (Na2SiO3) in ammonium chloride (NH4Cl). The surface bonding, phase constitution and chemical components of the samples were characterized by Fourier transform infrared spectroscopy (FT-IR), X-ray diffraction(XRD) and X-ray photoelectron spectroscopy (XPS). The mechanism of the SiO2 coating process onto TiO2 surface was analyzed. Results show that SiO2 particles were immobilized on the TiO2 surface via Ti—O—Si bondings, which formed at the interface. The SiO2 layer on TiO2 surface was amorphous, the photocatalytic performance was decreased of the TiO2 while its stability was enhanced after surface modification.

scholarly journals Synthesis of lead-based 1212 and 3212 superconductors by an aqueous sol-gel method

2009 ◽  
Vol 7 (3) ◽  
pp. 362-368 ◽  
Author(s):  
Giedre Nenartaviciene ◽  
Ramunas Skaudzius ◽  
Rimantas Raudonis ◽  
Aivaras Kareiva
Keyword(s):  
Sol Gel ◽  
Xrd Analysis ◽  
Structural Features ◽  
Complexing Agents ◽  
X Ray Diffraction ◽  
X Ray ◽  
Resistivity Measurements ◽  
Ceramic Samples ◽  
Xrd Patterns ◽  
Sol Gel Synthesis

AbstractThe aqueous sol-gel synthesis technique for the preparation of (Pb,Sr)Sr2(Y,Ca)Cu2O7±x (Pb-1212) and (Pb2,Cu)Sr2(Y,Ca)Cu2O8±x (Pb-3212) superconductors using two different complexing agents, namely 1,2-ethanediol and tartaric acid was studied. The phase transformations, composition and micro-structural features in the polycrystalline samples were studied by powder X-ray diffraction analysis (XRD), infrared spectroscopy (FTIR) and scanning electron microscopy (SEM). XRD analysis of the ceramic samples obtained by calcination of Pb-Sr-Y-Ca-Cu-O acetate-glycolate precursor gels in air, for 10 hours at 800°C and at 825°C, showed the presence of homogeneous Pb-1212 and Pb-3212 crystallites as major phases. The XRD patterns of the ceramics obtained from Pb-Sr-Y-Ca-Cu-O acetate-tartrate precursor gels, however, showed multiphasic character. The critical temperature of superconductivity (TC (onset)) observed by resistivity measurements were found to be 91 K and 75 K for Pb-1212 and Pb-3212 samples, respectively.

Sol-gel synthesis and characterization of CuO–based nanosystems

2002 ◽  
Vol 737 ◽  
Author(s):  
Lidia Armelao ◽  
Davide Barreca ◽  
Manuel Bertapelle ◽  
Gregorio Bottaro ◽  
Cinzia Sada ◽  
...  
Keyword(s):  
Photoelectron Spectroscopy ◽  
Sol Gel ◽  
Copper Acetate ◽  
Dip Coating ◽  
Silica Matrix ◽  
Synthesis And Characterization ◽  
Host Matrix ◽  
X Ray ◽  
Sol Gel Synthesis

ABSTRACTThis paper is focused on the sol-gel synthesis and characterization of CuO-based nanosystems both in the form of supported films and as guest nanoclusters embedded in a silica matrix. In both cases copper acetate (Cu(CH3COO)2 · H2O) was used as Cu source and, for the CuO :SiO2 nanocomposite systems, tetraethoxysilane (Si(OC2H5)4, TEOS) was adopted as silica precursor. Films were obtained by a dip-coating procedure and subsequently treated in air between 100 and 900°C. The system evolution on thermal annealing was studied by X-ray photoelectron spectroscopy (XPS), Glancing-Incidence X-ray diffraction (GIXRD) and optical absorption. Irrespective of the processing conditions, the formation of tenorite (CuO) crystallites with nanometric dimension was observed. In the nanocomposite samples, copper was homogeneously distributed in the host matrix and stable CuO nanoclusters (φ ≈ 15 nm) were obtained.

scholarly journals Characterization of Tio2 And An As-Prepared Tio2/Sio2 Composite And Their Photocatalytic Performance For The Reduction Of Low-Concentration N-NO3- In Water

2021 ◽  
Author(s):  
Wanzhen Zhong ◽  
Weizhang Fu ◽  
Shujuan Sun ◽  
Lingsheng Wang ◽  
Huaihao Liu ◽  
...  
Keyword(s):  
Photoelectron Spectroscopy ◽  
Photocatalytic Performance ◽  
Uv Light ◽  
Removal Rate ◽  
Sol Gel ◽  
X Ray Diffraction ◽  
X Ray ◽  
Load Rate ◽  
Hole Scavenger ◽  
Ft Ir

Abstract Excessive N-NO3- water pollution has become a widespread and serious problem that threatens human and ecosystem health. Here, a TiO2/SiO2 composite photocatalyst was prepared via the sol-gel/hydrothermal method. TiO2 and TiO2/SiO2 were characterized by X-ray diffraction (XRD), UV-Vis differential reflectance spectroscopy (DRS), Fourier infrared (FT-IR) spectroscopy, X-ray photoelectron spectroscopy (XPS), scanning electron microscopy (SEM), and energy-dispersive X-ray spectroscopy (EDS). Afterward, the photocatalytic performance of TiO2 and TiO2/SiO2 to reduce low nitrate concentrations (30 mgN·L-1) under UV light were evaluated and the effects of different factors on this process were investigated, after which the reaction conditions were optimized. Removal rates of up to 99.93% were achieved at a hole scavenger (formic acid) concentration of 0.6 mL·L-1, a CO2 flow rate of 0.1 m3·h-1, and a TiO2 concentration of 0.9 g·L-1. In contrast, TiO2/SiO2 at a 1.4 g·L-1 concentration and a TiO2 load rate of 40% achieved a removal rate of 83.48%,But with more than 98% of nitrogen generation rate.NO2- and NH4+ were the minor products, whereas N2 was the main product.

Sol-gel Synthesis of Li–ZrSiO4

2000 ◽  
Vol 15 (7) ◽  
pp. 1490-1495 ◽  
Author(s):  
Heriberto Pfeiffer ◽  
Pedro Bosch ◽  
Jose A. Odriozola ◽  
Alberto Lopez ◽  
Jorge A. Ascencio ◽  
...  
Keyword(s):  
Theoretical Analysis ◽  
Photoelectron Spectroscopy ◽  
Sol Gel ◽  
Molar Ratio ◽  
Spectroscopy Analysis ◽  
Gel Method ◽  
X Ray ◽  
Cell Parameters ◽  
Molar Ratios ◽  
Sol Gel Synthesis

Li–ZrSiO4 was synthesized by the sol-gel method. Reactions were performed with different Li:Zr molar ratios: 1, 3, 5, and 6. Cell parameters changed as follows: a0 decreased and c0 increased as the Li:Zr molar ratio increased. The x-ray photoelectron spectroscopy analysis showed two kinds of oxygen atoms. The first one was attributed to ZrSiO4 oxygens. The second one was attributed to Li–O bonds. All these results were supported by a theoretical analysis. It was concluded that lithium atoms were held in interstitial positions of the ZrSiO4 structure.

Sol–Gel Synthesis and Yellow Luminescent Properties of Zn2SiO4 :V Nanophosphor Materials

2019 ◽  
Vol 14 (12) ◽  
pp. 1796-1803
Author(s):  
Jaber El Ghoul ◽  
Naglaa Abdel All
Keyword(s):  
Photoelectron Spectroscopy ◽  
Sol Gel ◽  
Visible Region ◽  
Luminescent Properties ◽  
Structural Morphology ◽  
Host Matrix ◽  
X Ray ◽  
Transmission Electron ◽  
Color Tunable ◽  
Sol Gel Synthesis

Pure Zn2SiO4 and Vanadium doped Zn2SiO4 green nanophosphor materials were synthesized using sol–gel method and thermally annealed at 1500 °C. The structural, morphology and optical properties were characterized using various techniques; X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), Scanning electron microscope (SEM), high resolution transmission electron microscopy (HTEM), and photoluminescence spectroscopy (PL). XRD results shown β-Zn2SiO4 phase with triclinic structure that obtained after the heat treatment of samples at 1500 °C. The PL spectrum of V-Zn2SiO4 shows an intensive emission band in the visible region centered at 526 nm. This band is related to presence of vanadium in the interfaces between Zn2SiO4 nanoparticles and the host matrix, SiO2. The interesting of these nanophosphors were attributed for its capability of showing color-tunable emissions in visible region under a single-wavelength excitation.

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