scholarly journals Photocatalytic Hydrogen Production Under Near-UV Using Pd-Doped Mesoporous TiO2 and Ethanol as Organic Scavenger

Catalysts ◽  
2019 ◽  
Vol 9 (1) ◽  
pp. 33 ◽  
Author(s):  
Bianca Rusinque ◽  
Salvador Escobedo ◽  
Hugo de Lasa
Keyword(s):  
Hydrogen Production ◽  
Uv Light ◽  
Sol Gel ◽  
Chemical Reactor ◽  
Morphological Properties ◽  
Soft Template ◽  
Quantum Yields ◽  
Metal Doped ◽  
The University ◽  
Energy Balances

Photocatalysis can be used advantageously for hydrogen production using a light source (near-UV light), a noble metal-doped semiconductor and an organic scavenger (2.0 v/v% ethanol). With this end, palladium was doped on TiO2 photocatalysts at different metal loadings (0.25 to 5.00 wt%). Photocatalysts were synthetized using a sol-gel method enhancing morphological properties with a soft template precursor. Experiments were carried out in the Photo-CREC Water II reactor system developed at CREC-UWO (Chemical Reactor Engineering Centre- The University of Western Ontario) Canada. This novel unit offers hydrogen storage and symmetrical irradiation allowing precise irradiation measurements for macroscopic energy balances. Hydrogen production rates followed in all cases a zero-order reaction, with quantum yields as high as 30.8%.

scholarly journals Preparation and Characterization of Nanocrystalline TiO2 on Microsericite for High-Efficiency Photo-Energy Conversion of Methanol to Hydrogen

Crystals ◽  
2019 ◽  
Vol 9 (8) ◽  
pp. 380 ◽  
Author(s):  
Huang ◽  
Wu ◽  
Nguyen ◽  
Nguyen
Keyword(s):  
Acetic Acid ◽  
Hydrogen Production ◽  
Energy Conversion ◽  
High Efficiency ◽  
Uv Light ◽  
Sol Gel ◽  
Nitrogen Adsorption ◽  
Absorption Spectrometry ◽  
Nanocrystalline Tio2 ◽  
Bet Theory

TiO2 and TiO2/sericite photocatalysts were successfully synthesized via the sol-gel method by adding a varying amount of acetic acid. The effect of acetic acid on TiO2 and TiO2/sericite photocatalysts was studied. The crystallite size, surface morphology, chemical composition, specific surface area, surficial functional groups, and light absorbance of the prepared photocatalysts were revealed by the analysis of X-ray diffraction (XRD), scanning electron microscope-energy dispersive spectrometry (SEM-EDS), nitrogen adsorption-desorption isotherms by using BET theory (Brunauer–Emmett–Teller), Fourier-transform infrared spectroscopy (FTIR), and UV-Vis absorption spectrometry. Photo-energy conversion of methanol to hydrogen was also conducted over the prepared photocatalysts. The best hydrogen production was achieved by using the TiO2/sericite photocatalyst to give a hydrogen production rate of 1424 μmol/g·h in 6 h of UV-light irradiation.

scholarly journals Tailoring Mesoporous Titania Features by Ultrasound-Assisted Sol-Gel Technique: Effect of Surfactant/Titania Precursor Weight Ratio

Nanomaterials ◽  
2021 ◽  
Vol 11 (5) ◽  
pp. 1263
Author(s):  
Elvira Mahu ◽  
Cristina Giorgiana Coromelci ◽  
Doina Lutic ◽  
Iuliean Vasile Asaftei ◽  
Liviu Sacarescu ◽  
...  
Keyword(s):  
Photocatalytic Activity ◽  
Sol Gel ◽  
Weight Ratio ◽  
Soft Template ◽  
Synthesis Process ◽  
Mesoporous Titania ◽  
Cavitation Effect ◽  
Titania Precursor ◽  
Gel Technique ◽  
Ultrasound Assisted

A mesoporous titania structure has been prepared using the ultrasound-assisted sol-gel technique in order to find out a way to tailor its structure. The TiO2 obtained was compared to the same version of titania but synthesized by a conventional sol-gel method with the objective of understanding the effect of ultrasound in the synthesis process. All synthesis experiments were focused on the preparation of a titania photocatalyst. Thus, the anatase photocatalytic active phase of titania was proven by X-ray diffraction. Additionally, the ultrasonation treatment proved to increase the crystallinity of titania samples, being one of the requirements to having good photocatalytic activity for titania. The influence of surfactant/titania precursor weight ratio on the structural (XRD), textural (N2-sorption measurements), morphological (TEM), surface chemistry (FTIR) and optical properties (UVDR) was investigated. It was observed that the crystallite size, specific surface area, band gap energy and even photocatalytic activity was affected by the synergism occurring between cavitation effect and the surfactant/titania precursor weight ratio. The study yielded interesting great results that could be considered for further application of ultrasound to tailor mesoporous titania features via sol-gel soft template synthesis, against conventional sol-gel process.

scholarly journals TiO2-Powdered Activated Carbon (TiO2/PAC) for Removal and Photocatalytic Properties of 2-Methylisoborneol (2-MIB) in Water

Water ◽  
2021 ◽  
Vol 13 (12) ◽  
pp. 1622
Author(s):  
Xiao-Pin Guo ◽  
Peng Zang ◽  
Yong-Mei Li ◽  
Dong-Su Bi
Keyword(s):  
Activated Carbon ◽  
Natural Organic Matter ◽  
Uv Light ◽  
Sol Gel ◽  
Light Irradiation ◽  
Nano Tio2 ◽  
Uv Light Irradiation ◽  
Adsorption Capacities ◽  
Taste And Odor ◽  
Composite Photocatalysts

2-methylisoborneol (2-MIB) is a common taste and odor compound caused by off-flavor secondary metabolites, which represents one of the greatest challenges for drinking water utilities worldwide. A TiO2-coated activated carbon (TiO2/PAC) has been synthesized using the sol-gel method. A new TiO2/PAC photocatalyst has been successfully employed in photodegradation of 2-MIB under UV light irradiation. In addition, the combined results of XRD, SEM-EDX, FTIR and UV-Vis suggested that the nano-TiO2 had been successfully loaded on the surface of PAC. Experimental results of 2-MIB removal indicated that the adsorption capacities of PAC for 2-MIB were higher than that of TiO2/PAC. However, in the natural organic matter (NOM) bearing water, the removal efficiency of 2-MIB by TiO2/PAC and PAC were 97.8% and 65.4%, respectively, under UV light irradiation. Moreover, it was shown that the presence of NOMs had a distinct effect on the removal of MIB by TiO2/PAC and PAC. In addition, a simplified equivalent background compound (SEBC) model could not only be used to describe the competitive adsorption of MIB and NOM, but also represent the photocatalytic process. In comparison to other related studies, there are a few novel composite photocatalysts that could efficiently and rapidly remove MIB by the combination of adsorption and photocatalysis.

Preparation and Photocatalytic Activity of TiO2/Opal Composite

2013 ◽  
Vol 668 ◽  
pp. 13-16
Author(s):  
Qing Shan Li ◽  
Biao Zhan ◽  
Wei Hong ◽  
Guang Zhong Xing
Keyword(s):  
Methylene Blue ◽  
Uv Light ◽  
Sol Gel ◽  
Tetrabutyl Titanate ◽  
Methylene Blue Solution ◽  
Photocatalytic Decolorization ◽  
Uv Light Irradiation ◽  
Photocatalytic Activities ◽  
Blue Solution ◽  
Gel Technique

Opal as a carrier, tetrabutyl titanate as a titanium source, TiO2 loaded on opal was prepared by sol-gel technique. The photocatalysts were characterized by XRD, TEM and UV-VIS absorption spectrum. Their photocatalytic activities were examined by the photocatalytic decolorization of methylene blue solution under UV light irradiation. The effects of calcination temperature, the amount of TiO2 loading and pH on photocatalytic activities were discussed. The results show that TiO2 supported on opal induced enhancement of photocatalytic decolorization rant and TiO2 doping is about 30 wt. % with 92.15% of decolorization rate at 700°C.

Optic and Piezoelectric Coupling in the Sol-Gel PLZT Electroceramics

2012 ◽  
Vol 730-732 ◽  
pp. 129-134
Author(s):  
Lucjan Kozielski ◽  
Malgorzata Plonska
Keyword(s):  
Uv Light ◽  
Sol Gel ◽  
Light Illumination ◽  
Piezoelectric Effects ◽  
Piezoelectric Coupling ◽  
Wireless Device ◽  
Organometallic Precursors ◽  
Gain Adjustment ◽  
Piezoelectric Transformers ◽  
Sintering Method

PZT ceramic system with presence of La contents, have been proposed and prepared using sol gel sintering method for practical application of photostriction, which is the superposition of photovoltaic and piezoelectric effects. Such a ceramics produced by conventional mixing oxide method does not exhibit photostrictive properties due to the defects and inhomogeneous distribution of grains and pores. In this study, an investigated lanthanium(III) doped PZT ceramics were obtained by sol-gel technique from the organometallic precursors. It was found that fabricated material were effective in the enhancement of photovoltaic and photostrictive properties. Consequently, lanthanium influence deviation of piezoelectric parameters were studied as a function UV light illumination. For the determination lighting dependancy of the transformation parameters the resonant and antiresonant method was implemented. The improved Piezoelectric Transformer structure successfully changed gain characteristics proportionally to light intensity. The authors invention of a light driven output gain adjustment in Piezoelectric Transformers (PT) yields a novel “smart” multifunctional wireless device. This new created application area can be utilized in self-adopting shutters in photo cameras due to improved sensitivity to surrounding illumination conditions.

scholarly journals Synthesis and Characterization of Nanocrystalline ZnO Doped with Al3+ and Ni2+ by a Sol–Gel Method Coupled with Ultrasound Irradiation

Crystals ◽  
2018 ◽  
Vol 8 (11) ◽  
pp. 406 ◽  
Author(s):  
M. Robles-Águila ◽  
J. Luna-López ◽  
Álvaro Hernández de la Luz ◽  
J. Martínez-Juárez ◽  
M. Rabanal
Keyword(s):  
Sol Gel ◽  
Nitrogen Adsorption ◽  
Ultrasound Irradiation ◽  
Morphological Properties ◽  
Nanocrystalline Powders ◽  
Metallic Ions ◽  
Gel Method ◽  
X Ray ◽  
Sol Gel Method ◽  
Doped Zno

Zinc oxide is one of the most important semiconducting metal oxides and one of the most promising n-type materials, but its practical use is limited because of both its high thermal conductivity and its low electrical conductivity. Numerous studies have shown that doping with metals in ZnO structures leads to the modification of the band gap energy. In this work, Al-doped ZnO, Ni-doped ZnO, and undoped ZnO nanocrystalline powders were prepared by a sol–gel method coupled with ultrasound irradiation, and the results show the influence of Al3+ and Ni2+ ions in the ZnO network. The doping concentrations in ZnO of 0.99 atom % for ZnO–Al and 0.80 atom % for ZnO–Ni were obtained by X-ray Fluorescence (XRF). X-ray Diffraction (XRD) and Raman Spectroscopy showed a decreased intensity and broadening of main peaks, indicating metallic ions. The crystallite size of the sample was decreased from 24.5 nm (ZnO) to 22.0 nm (ZnO–Al) and 21 nm (ZnO–Ni). The textural and morphological properties were analyzed via Nitrogen Adsorption (BET method) and Field Emission Scanning Electron Microscopy (FESEM).

Sol-gel-derived gallium nitride thin films for ultraviolet photodetection

2019 ◽  
Vol 36 (1) ◽  
pp. 8-13 ◽  
Author(s):  
Chee Yong Fong ◽  
Sha Shiong Ng ◽  
NurFahana Mohd Amin ◽  
Fong Kwong Yam ◽  
Zainuriah Hassan
Keyword(s):  
Thin Films ◽  
Dark Current ◽  
Uv Light ◽  
Low Cost ◽  
Sol Gel ◽  
Contrast Ratio ◽  
Uv Photodetector ◽  
Content Type ◽  
Barrier Heights ◽  
Coating Method

Purpose This study aims to explore the applicability of the sol-gel-derived GaN thin films for UV photodetection. Design/methodology/approach GaN-based ultraviolet (UV) photodetector with Pt Schottky contacts was fabricated and its applicability was investigated. The current-voltage (I-V) characteristics of the GaN-based UV photodetector under the dark current and photocurrent were measured. Findings The ideality factors of GaN-based UV photodetector under dark current and photocurrent were 6.93 and 5.62, respectively. While the Schottky barrier heights (SBH) for GaN-based UV photodetector under dark current and photocurrent were 0.35 eV and 0.34 eV, respectively. The contrast ratio and responsivity of this UV photodetector measured at 5 V were found to be 1.36 and 1.68 μA/W, respectively. The photoresponse as a function of time was measured by switching the UV light on and off continuously at different forward biases of 1, 3 and 6 V. The results showed that the fabricated UV photodetector has reasonable stability and repeatability. Originality/value This work demonstrated that GaN-based UV photodetector can be fabricated by using the GaN thin film grown by low-cost and simple sol-gel spin coating method.

scholarly journals Silica synthesis by the sol-gel method and its use in the preparation of multifunctional biocomposites

2014 ◽  
Vol 12 (2) ◽  
pp. 173-184 ◽  
Author(s):  
Łukasz Klapiszewski ◽  
Michał Królak ◽  
Teofil Jesionowski
Keyword(s):  
Electrode Materials ◽  
Sol Gel ◽  
Statistical Design ◽  
Morphological Properties ◽  
Statistical Design Of Experiments ◽  
Organic Precursor ◽  
Gel Method ◽  
Sol Gel Method ◽  
Non Invasive ◽  
Silica Synthesis

AbstractThis study focuses on the optimization process of silica synthesis using the sol-gel method while applying a statistical design of experiments which was based on a multilevel mathematical model. The product obtained in the process of optimized synthesis, characterized by the best dispersive and morphological parameters, was used for the preparation of organic/inorganic composites. The organic precursor was Kraft lignin, a high-molecular natural polymer. Synthesis of silica/lignin biocomposites was carried out by three proposed methods. The physicochemical properties and dispersive-morphological properties of each product were determined using the following available methods: Scanning Electron Microscopy — SEM, Non-Invasive Back-Scattering — NIBS, Fourier Transform Infrared Spectroscopy — FT-IR, Thermogravimetric analysis — TG and others. The electrokinetic and thermal properties of the biocomposites sufficed to be applied for example, as a cheap and biodegradable polymer filler. Further areas of application of these composites were sought, especially in electrochemistry as the advanced electrode materials.

scholarly journals Tuning the Morphological Properties of Cellulose Aerogels: An Investigation of Salt-Mediated Preparation

2021 ◽  
Author(s):  
Prakash Parajuli ◽  
Sanjit Acharya ◽  
Julia Shamshina ◽  
Noureddine Abidi
Keyword(s):  
Specific Surface ◽  
Surface Area ◽  
Specific Surface Area ◽  
Sol Gel ◽  
Earth Metal ◽  
Morphological Properties ◽  
Cellulose Solution ◽  
Bet Analysis ◽  
Sol Gel Transition ◽  
Gel Transition

Abstract In this study, alkali and alkaline earth metal chlorides with different cationic radii (LiCl, NaCl, and KCl, MgCl2, and CaCl2) were used to gain insight into the behavior of cellulose solutions in the presence of salts. The specific focus of the study was evaluation of the effect of salts’ addition on the sol-gel transition of the cellulose solutions and on their ability to form monoliths, as well as evaluation of the morphology (e.g., specific surface area, pore characteristics, and microstructure) of aerocelluloses prepared from these solutions. The effect of the salt addition on the sol-gel transition of cellulose solutions was studied using rheology, and morphology of resultant aerogels was evaluated by Scanning Electron Microscopy (SEM) and Brunauer-Emmett-Teller (BET) analysis, while the salt influence on the aerocelluloses’ crystalline structure and thermal stability was evaluated using powder X-Ray Diffraction (pXRD) and Thermogravimetric Analysis (TGA), respectively. The study revealed that the effect of salts’ addition was dependent on the component ions and their concentration. The addition of salts in the amount below certain concentration limit significantly improved the ability of the cellulose solutions to form monoliths and reduced the sol-gel transition time. Salts of lower cationic radii had a greater effect on gelation. However, excessive amount of salts resulted in the formation of fragile monoliths or no formation of gels at all. Analysis of surface morphology demonstrated that the addition of salts resulted in a significant increase in porosity and specific surface area, with salts of lower cationic radii leading to aerogels with much larger (~1.5 and 1.6-fold for LiCl and MgCl2, respectively) specific surface area compared to aerocelluloses prepared with no added salt. Thus, by adding the appropriate salt into the cellulose solution prior to gelation, the properties of aerocelluloses that control material’s performance (specific surface area, density, and porosity) could be tailored for a specific application.

scholarly journals Synthesis and Characterization of Boron, Copper, and Zinc-Doped Hydroxyapatite by Sol-Gel Method: Research of Absorption and Thermal Behavior

2021 ◽  
Author(s):  
Dilek Çanakçı
Keyword(s):  
Thermal Behavior ◽  
Sol Gel ◽  
Absorption Bands ◽  
Gel Method ◽  
X Ray ◽  
Sol Gel Method ◽  
Copper And Zinc ◽  
Vis Spectroscopy ◽  
Metal Doped

Abstract In this study, hydroxyapatites reinforced with Boron, Copper and Zinc at different rates were produced using the sol-gel method. Different amounts of metal during the production of hydroxyapatite were used to observe the amount of crystallization and morphological differences in their structures. The characterization of the metal-doped HAp was carried out by X-ray diffraction (XRD), Fourier transform infrared (FTIR) spectroscopy, scanning electron microscopy (SEM) and Energy-dispersive X-ray spectroscopy (EDX). The data indicated that the Ca/P stoichiometric ratios of the samples varied between 1.71 and 2, so their morphologies were different from each other. The absorption behavior of novel metal-doped HAp samples was evaluated at room temperature by UV-vis spectroscopy. In the absorption spectra of the samples, absorption bands formed in similar regions. In addition, the thermal behavior of HAp samples was investigated using TG/DTA techniques. The results of the analysis showed that heat resistance of the new synthesized samples was quite high.

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