scholarly journals Superacid ZrO2–SiO2–SnO2 Mixed Oxide: Synthesis and Study

2021 ◽  
Vol 15 (3) ◽  
pp. 336-342
Author(s):  
Svitlana Prudius ◽  
◽  
Natalia Hes ◽  
Volodymyr Trachevskiy ◽  
Oleg Khyzhun ◽  
...  
Keyword(s):  
Acetic Anhydride ◽  
Mixed Oxide ◽  
Nmr Spectra ◽  
Flow Reactor ◽  
Sol Gel ◽  
Atomic Ratio ◽  
Acid Sites ◽  
29Si Mas Nmr ◽  
Xps Spectra ◽  
Silicon Ions

Superacid ternary ZrO2 SiO2 SnO2 oxide has been synthesized by the sol-gel method with a different atomic ratio Zr:Si:Sn. The highest strength of acid sites has been observed in the ranges of 20 ≤ Zr4+ ≤ 29, 60 ≤ Si4+ ≤ 67, 11 ≤ Sn4+ ≤ 20 at.%. According to the XPS spectra and 119Sn, 29Si MAS NMR spectra of ZrO2 SiO2 SnO2 a partial shift of electron density from zirconium to silicon ions was observed resulting in the formation of superacid Lewis sites. It was shown that superacid Zr29Si60Sn11 mixed oxide efficiently catalyzes acylation of toluene with acetic anhydride at 423 K in a flow reactor with 45% conversion of anhydride at 100% selectivity towards p-methylacetophenone.

Bisphenol A Imprinted SiO2‐ZrO2 Mixed Oxide Materials Prepared by Acetic Anhydride Sol‐Gel Method

2007 ◽  
Vol 37 (10) ◽  
pp. 771-777 ◽  
Author(s):  
Masahiro Fujiwara ◽  
Ikou Yamamura ◽  
Motoyasu Nishiyama ◽  
Kumi Shiokawa ◽  
Souichi Ohtsuki ◽  
...  
Keyword(s):  
Acetic Anhydride ◽  
Bisphenol A ◽  
Mixed Oxide ◽  
Sol Gel ◽  
Oxide Materials ◽  
Gel Method ◽  
Sol Gel Method

scholarly journals Tuned S-Scheme Cu2S_TiO2_WO3 Heterostructure Photocatalyst toward S-Metolachlor (S-MCh) Herbicide Removal

Materials ◽  
2021 ◽  
Vol 14 (9) ◽  
pp. 2231
Author(s):  
Alexandru Enesca ◽  
Luminita Isac
Keyword(s):  
Sol Gel ◽  
Annealing Treatment ◽  
Atomic Ratio ◽  
High Concentration ◽  
Step Procedure ◽  
Constant Rate ◽  
Efficient Charge ◽  
Crystallite Sizes ◽  
Oxygen Excess ◽  
And Migration

A dual S-scheme Cu2S_TiO2_WO3 heterostructure was constructed by sol–gel method using a two-step procedure. Due to the synthesis parameters and annealing treatment the heterostructure is characterized by sulfur deficit and oxygen excess allowing the passivation of oxygen vacancies. The photocatalytic activity was evaluated under UV and UV–Vis irradiation scenarios using S-MCh as reference pollutant. The heterostructure is composed on orthorhombic Cu2S, anatase TiO2 and monoclinic WO3 with crystallite sizes varying from 65.2 Å for Cu2S to 97.1 Å for WO3. The heterostructure exhibit a dense morphology with pellets and particle-like morphology closely combined in a relatively compact assembly. The surface elemental composition indicate that the heterostructure maintain a similar atomic ratio as established during the synthesis with a slight sulfur deficit due to the annealing treatments. The results indicate that the three-component heterostructure have higher photocatalytic efficiency (61%) comparing with two-component heterostructure or bare components. Moreover, Cu2S_TiO2_WO3 exhibit a superior constant rate (0.114 s−1) due to the high concentration of photogenerated charge carriers, efficient charge separation and migration.

scholarly journals Green Synthesis of N/Zr Co-Doped TiO2 for Photocatalytic Degradation of p-Nitrophenol in Wastewater

Catalysts ◽  
2021 ◽  
Vol 11 (2) ◽  
pp. 235
Author(s):  
Hayette Benkhennouche-Bouchene ◽  
Julien G. Mahy ◽  
Cédric Wolfs ◽  
Bénédicte Vertruyen ◽  
Dirk Poelman ◽  
...  
Keyword(s):  
Visible Light ◽  
Tio2 Nanoparticles ◽  
Sol Gel ◽  
Visible Region ◽  
Chemical Properties ◽  
Pure Tio2 ◽  
Molar Ratio ◽  
Xps Spectra ◽  
Doped Tio2 ◽  
Co Doped

TiO2 prepared by a green aqueous sol–gel peptization process is co-doped with nitrogen and zirconium to improve and extend its photoactivity to the visible region. Two nitrogen precursors are used: urea and triethylamine; zirconium (IV) tert-butoxide is added as a source of zirconia. The N/Ti molar ratio is fixed regardless of the chosen nitrogen precursor while the quantity of zirconia is set to 0.7, 1.4, 2, or 2.8 mol%. The performance and physico-chemical properties of these materials are compared with the commercial Evonik P25 photocatalyst. For all doped and co-doped samples, TiO2 nanoparticles of 4 to 8 nm of size are formed of anatase-brookite phases, with a specific surface area between 125 and 280 m2 g−1 vs. 50 m2 g−1 for the commercial P25 photocatalyst. X-ray photoelectron (XPS) measurements show that nitrogen is incorporated into the TiO2 materials through Ti-O-N bonds allowing light absorption in the visible region. The XPS spectra of the Zr-(co)doped powders show the presence of TiO2-ZrO2 mixed oxide materials. Under visible light, the best co-doped sample gives a degradation of p-nitrophenol (PNP) equal to 70% instead of 25% with pure TiO2 and 10% with P25 under the same conditions. Similarly, the photocatalytic activity improved under UV/visible reaching 95% with the best sample compared to 50% with pure TiO2. This study suggests that N/Zr co-doped TiO2 nanoparticles can be produced in a safe and energy-efficient way while being markedly more active than state-of-the-art photocatalytic materials under visible light.

scholarly journals Liquid Phase Benzylation of Toluene over Modified Titania Catalysts

2012 ◽  
Vol 11 (2) ◽  
pp. 31-44
Author(s):  
Sunaja Devi K R ◽  
Sugunan S
Keyword(s):  
Liquid Phase ◽  
Lewis Acid ◽  
Benzyl Chloride ◽  
Sol Gel ◽  
Active Phase ◽  
Temperature Programmed Desorption ◽  
Acid Sites ◽  
Lewis Acid Sites ◽  
Sulfated Titania ◽  
Temperature Programmed

Titania, sulfated titania and a series of iron loaded sulfated titania catalyst with different iron loadings (39 %) are prepared by sol-gel method and calcined at 500°C. Anatase is found to be the active phase with crystallite size in the nano range. All the prepared catalysts are found to be stable up to 700°C. Acidity is measured using spectrophotometric monitoring of adsorption of perylene, thermogravimetric desorption of 2,6-dimethylpyridine and temperature programmed desorption of ammonia. The activities of the catalysts were tested for liquid phase Friedel-Crafts benzylation of toluene with benzyl chloride. It has been concluded that Lewis acid sites are responsible for the reaction.

A Sol-Gel Ruthenium-Niobium-Silicon Mixed-Oxide Bifunctional Catalyst for the Hydrogenation of Levulinic Acid in the Aqueous Phase

ChemCatChem ◽  
2017 ◽  
Vol 9 (8) ◽  
pp. 1476-1486 ◽  
Author(s):  
Luciana Minieri ◽  
Serena Esposito ◽  
Vincenzo Russo ◽  
Barbara Bonelli ◽  
Martino Di Serio ◽  
...  
Keyword(s):  
Aqueous Phase ◽  
Mixed Oxide ◽  
Levulinic Acid ◽  
Sol Gel ◽  
Bifunctional Catalyst

scholarly journals Photocatalytic Properties of Nitrogen-Doped Bi12TiO20Synthesized by Urea Addition Sol-Gel Method

2012 ◽  
Vol 2012 ◽  
pp. 1-8 ◽  
Author(s):  
Jiyong Wei ◽  
Baibiao Huang ◽  
Peng Wang ◽  
Zeyan Wang ◽  
Xiaoyan Qin ◽  
...  
Keyword(s):  
Nitrogen Doping ◽  
Diffuse Reflection ◽  
Sol Gel ◽  
Photocatalytic Properties ◽  
Xps Spectra ◽  
Gel Method ◽  
Sol Gel Method ◽  
Nitrogen Doped ◽  
Heavily Doped ◽  
Urea Addition

Undoped and nitrogen-doped Bi12TiO20materials were synthesized by urea addition sol-gel method. By adding urea, undoped, and N-doped gel-type precursors were synthesized by low-temperature dehydrolyzation. Nitrogen-doped and undoped nanocrystalline Bi12TiO20were prepared by annealing at 600∘C for 30 minutes. From UV-Vis absorption and diffuse reflection spectrum, the absorbing band shifted from 420 to 500 nm by nitrogen doping. The bonds of Ti–N and N–O were identified by XPS spectra from the prepared materials, and the enhancement of visible light absorption was attributed to nitrogen's substitution of oxygen. Photocatalytic properties of prepared materials were characterized by the decomposition of Rhodamine B illuminated by whole spectra of 300 W Xe light. The photocatalystBi12TiO20−yNy(y=0.03) with N/(N+O) mole ratio about 3% shows better performance than that of heavily dopedBi12TiO20−zNz(z=0.06), undoped Bi12TiO20, and light-dopedBi12TiO20−xNx(x=0.01) photocatalysts due to its better crystalline morphology.

scholarly journals Catalytic myrtenol amination over gold, supported on alumina doped with ceria and zirconia

2018 ◽  
Vol 5 (1) ◽  
pp. 49-58 ◽  
Author(s):  
Yu.S. Demidova ◽  
I.L. Simakova ◽  
E.V. Suslov ◽  
K.P. Volcho ◽  
N.F. Salakhutdinov ◽  
...  
Keyword(s):  
Metal Oxides ◽  
Sol Gel ◽  
Gold Catalyst ◽  
Catalyst Support ◽  
Acid Sites ◽  
One Pot ◽  
Gel Method ◽  
Sol Gel Method ◽  
Alcohol Activation ◽  
The One

Abstract In the current work gold catalysts supported on both commercial oxides and oxides synthesized by the sol-gel method were used for the one-pot alcohol amination of myrtenol. In general, utilization of metal oxides synthesized by the sol-gel method as the gold catalyst support enhanced the knowledge regarding key parameters determining catalytic behavior. Synthesized alumina was characterized by stronger acid sites favoring primary amine accumulation on the catalyst surface, as compared to the commercial oxide. Utilization of mixed metal oxides synthesized by the sol-gel method resulted in the non-additive behavior of different oxides enhancing the catalytic activity. Introduction of ceria into alumina modified the support basicity resulting in more efficient alcohol activation.

Sign in / Sign up

Export Citation Format

Share Document