Sol–gel assisted hydrothermal synthesis of ZnO microstructures: Morphology control and photocatalytic activity

Background: The properties of the material are altered when material size shifted towards nano-regime. This feature could be used for wastewater treatment process using model pollutant such as dyes. Recently, nanoparticles are synthesized by a green chemical route using different capping agents. This is the reason we adopt starch as green capping agent along with sol-gel method. Objective: To synthesize cobalt oxide nanoparticles by green chemical route and utilized it in degradation of dyes. Methods: Synthesis of cobalt oxide nanoparticles by sol-gel method using starch as a capping agent. The characteristics of surface modifications were investigated by UV-VIS, TEM, SEM, XRD and FTIR techniques. Results: Cobalt oxide nanoparticles synthesized and inhibited photocatalytic activity. Conclusion: Deactivation of photocatalytic activity due to complex nature of starch. This property can be used elsewhere as in light shielding applications to coat and protect surfaces in order to keep them cool and safe from damage as in the painting of vehicles, roofs, buildings, water tanks, etc.

Download Full-text

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

Nanomaterials ◽

10.3390/nano11051263 ◽

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.

Download Full-text

Photocatalytic activity of Pr-modified TiO2 for the degradation of bisphenol A

SN Applied Sciences ◽

10.1007/s42452-021-04284-2 ◽

2021 ◽

Vol 3 (2) ◽

Author(s):

Denise S. Cordeiro ◽

Fernando L. Cassio ◽

Larissa Ciccotti ◽

Thiago L. R. Hewer ◽

Paola Corio ◽

...

Keyword(s):

Photocatalytic Activity ◽

Bisphenol A ◽

Pore Diameter ◽

Sol Gel ◽

Bandgap Energy ◽

Photocatalytic Efficiency ◽

Average Pore ◽

X Ray ◽

Vis Spectroscopy ◽

Adsorption Desorption

AbstractPraseodymium doped TiO2 nanoparticles were successfully prepared by the sol–gel method and characterized by X-ray powder diffraction, N2 adsorption–desorption isotherm, and UV–vis spectroscopy. The effects of the dopant on the crystallite size, specific surface area, average pore diameter, pore volume, and bandgap energy were investigated. The photocatalytic activity of the catalysts was evaluated by bisphenol A degradation and mineralization, which is a representative endocrine disruptor. Furthermore, under visible light irradiation the Pr-modified TiO2 photocatalysts exhibited higher photocatalytic efficiency than unmodified TiO2. When praseodymium was loaded (1.0–5.0%) onto the surface of TiO2, the rates of degradation and mineralization were increased 3–5 times.

Download Full-text

Enhanced Photocatalytic Activity of CuWO4 Doped TiO2 Photocatalyst Towards Carbamazepine Removal under UV Irradiation

Separations ◽

10.3390/separations8030025 ◽

2021 ◽

Vol 8 (3) ◽

pp. 25

Author(s):

Chukwuka Bethel Anucha ◽

Ilknur Altin ◽

Emin Bacaksız ◽

Tayfur Kucukomeroglu ◽

Masho Hilawie Belay ◽

...

Keyword(s):

Electron Microscopy ◽

Photocatalytic Activity ◽

Photoelectron Spectroscopy ◽

Diffuse Reflectance Spectroscopy ◽

Sol Gel ◽

Pure Tio2 ◽

Component Part ◽

Energy Yield ◽

Mechanical Agitation ◽

X Ray

Abatement of contaminants of emerging concerns (CECs) in water sources has been widely studied employing TiO2 based heterogeneous photocatalysis. However, low quantum energy yield among other limitations of titania has led to its modification with other semiconductor materials for improved photocatalytic activity. In this work, a 0.05 wt.% CuWO4 over TiO2 was prepared as a powder composite. Each component part synthesized via the sol-gel method for TiO2, and CuWO4 by co-precipitation assisted hydrothermal method from precursor salts, underwent gentle mechanical agitation. Homogenization of the nanopowder precursors was performed by zirconia ball milling for 2 h. The final material was obtained after annealing at 500 °C for 3.5 h. Structural and morphological characterization of the synthesized material has been achieved employing X-ray diffraction (XRD), Fourier transform infra-red (FTIR) spectroscopy, Brunauer–Emmett–Teller (BET) N2 adsorption–desorption analysis, Scanning electron microscopy-coupled Energy dispersive X-ray spectroscopy (SEM-EDS), Transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS), and UV-Vis diffuse reflectance spectroscopy (UV-vis DRS) for optical characterization. The 0.05 wt.% CuWO4-TiO2 catalyst was investigated for its photocatalytic activity over carbamazepine (CBZ), achieving a degradation of almost 100% after 2 h irradiation. A comparison with pure TiO2 prepared under those same conditions was made. The effect of pH, chemical scavengers, H2O2 as well as contaminant ion effects (anions, cations), and humic acid (HA) was investigated, and their related influences on the photocatalyst efficiency towards CBZ degradation highlighted accordingly.

Download Full-text

Photocatalytic Activity Enhancement of Low-pressure Cold-Sprayed TiO2 Coatings Induced by Long-term Water Vapor Exposure

Journal of Thermal Spray Technology ◽

10.1007/s11666-021-01244-5 ◽

2021 ◽

Cited By ~ 1

Author(s):

Seremak Wioletta ◽

Baszczuk Agnieszka ◽

Jasiorski Marek ◽

Gibas Anna ◽

Winnicki Marcin

Keyword(s):

Titanium Dioxide ◽

Photocatalytic Activity ◽

Water Vapor ◽

Sol Gel ◽

Low Pressure ◽

Oxygen Depletion ◽

Amorphous Structure ◽

Industrial Applications ◽

Additional Parameter

AbstractThis work shows that the titanium dioxide coatings obtained by low-pressure cold gas spraying with the use of the sol–gel amorphous TiO2 powder are characterized by photocatalytic activity despite their partial amorphous content. Moreover, the research outcome suggests that the decomposition rate of organic pollutants is enhanced after long-term exposure to moisture. The condensation humidity test is not detrimental to the continuity and integrity of the coating, but the phase composition of coatings changes—with the exposure to water vapor, the portion of the amorphous phase crystallizes into brookite. The mechanism responsible for the conversion of amorphous TiO2 into brookite is attributed to the water-driven dissolution and reprecipitation of TiO6 octahedra. It has been shown that an additional parameter necessary for the stabilization of the brookite is the oxygen depletion of the amorphous structure of titanium dioxide. Considering the results presented in this paper and the advantages of a portable, low-pressure cold spray system for industrial applications, it is expected that TiO2 coatings produced from a sol–gel feedstock powder can be further developed and tested as efficient photocatalysts.

Download Full-text

Fabrication of tantalum oxyfluoride and oxynitride thin films via ammonolysis of sol–gel processed tetraethoxo (β-diketonato) tantalum (V) precursors for enhanced photocatalytic activity

Journal of Materials Science Materials in Electronics ◽

10.1007/s10854-021-05712-0 ◽

2021 ◽

Author(s):

Mohd. Danish ◽

Ashutosh Pandey ◽

Aftab Aslam Parwaz Khan ◽

Abdullah M. Asiri

Keyword(s):

Thin Films ◽

Photocatalytic Activity ◽

Sol Gel

Download Full-text

Hydrothermal synthesis and enhanced photocatalytic activity of Na0.5Gd0.5MoO4

Journal of Materials Science ◽

10.1007/s10853-021-06320-3 ◽

2021 ◽

Author(s):

Xuquan Wang ◽

Yang Li ◽

Fei Wang ◽

Baoqiang Xu ◽

Bin Yang ◽

...

Keyword(s):

Photocatalytic Activity ◽

Hydrothermal Synthesis

Download Full-text

Sol-Gel Synthesis of the Double Perovskite Sr2FeMoO6 by Microwave Technique

Materials ◽

10.3390/ma14143876 ◽

2021 ◽

Vol 14 (14) ◽

pp. 3876

Author(s):

Jesús Valdés ◽

Daniel Reséndiz ◽

Ángeles Cuán ◽

Rufino Nava ◽

Bertha Aguilar ◽

...

Keyword(s):

Particle Size ◽

Hydrothermal Synthesis ◽

Microwave Radiation ◽

Structural Characteristics ◽

Sol Gel ◽

Synthesis Method ◽

Double Perovskite ◽

Synthesis Methods ◽

X Ray ◽

Sol Gel Synthesis

The effect of microwave radiation on the hydrothermal synthesis of the double perovskite Sr2FeMoO6 has been studied based on a comparison of the particle size and structural characteristics of products from both methods. A temperature, pressure, and pH condition screening was performed, and the most representative results of these are herein presented and discussed. Radiation of microwaves in the hydrothermal synthesis method led to a decrease in crystallite size, which is an effect from the reaction temperature. The particle size ranged from 378 to 318 nm when pH was 4.5 and pressure was kept under 40 bars. According to X-ray diffraction (XRD) results coupled with the size-strain plot method, the product obtained by both synthesis methods (with and without microwave radiation) have similar crystal purity. The Scanning Electron Microscopy (SEM) and Energy Dispersive X-ray Spectroscopy (EDS) techniques showed that the morphology and the distribution of metal ions are uniform. The Curie temperature obtained by thermogravimetric analysis indicates that, in the presence of microwaves, the value was higher with respect to traditional synthesis from 335 K to 342.5 K. Consequently, microwave radiation enhances the diffusion and nucleation process of ionic precursors during the synthesis, which promotes a uniform heating in the reaction mixture leading to a reduction in the particle size, but keeping good crystallinity of the double perovskite. Precursor phases and the final purity of the Sr2FeMoO6 powder can be controlled via hydrothermal microwave heating on the first stages of the Sol-Gel method.

Download Full-text

Photocatalytic Degradation of Methylene Blue by NiO Thin Films under Solar Light Irradiation

Journal of Nano Research ◽

10.4028/www.scientific.net/jnanor.56.152 ◽

2019 ◽

Vol 56 ◽

pp. 152-157 ◽

Cited By ~ 5

Author(s):

Abdelouahab Noua ◽

Hichem Farh ◽

Rebai Guemini ◽

Oussama Zaoui ◽

Tarek Diab Ounis ◽

...

Keyword(s):

Thin Films ◽

Methylene Blue ◽

Photocatalytic Activity ◽

Sol Gel ◽

Visible Region ◽

Optical Transmittance ◽

Dip Coating ◽

Light Irradiation ◽

Solar Light ◽

Solar Light Irradiation

Nickel oxide (NiO) thin films were successfully deposited by sol-gel dip-coating method on glass substrates. The structural, morphological and optical properties in addition to the photocatalytic activity of the prepared films were investigated. The results show that the films have a polycrystalline NiO cubic structure with dense NiO grains and average optical transmittance in the visible region. The photocatalytic properties of the films were studied through the degradation of methylene blue and 89% of degradation was achieved for 4.5h of solar light irradiation exposure which indicates the capability of NiO photocatalytic activity.

Download Full-text