Chemical and Structural Changes by Gold Addition Using Recharge Method in NiW/Al2O3-CeO2-TiO2 Nanomaterials

NiWAu trimetallic nanoparticles (NPs) on the surface of support Al2O3-CeO2-TiO2 were synthesized by a three-step synthetic method in which Au NPs were incorporated into presynthesized NiW/Al2O3-CeO2-TiO2. The recharge method, also known as the redox method, was used to add 2.5 wt% gold. The Al2O3-CeO2-TiO2 support was made by a sol–gel method with two different compositions, and then two metals were simultaneously loaded (5 wt% nickel and 2.5 wt% tungsten) by two different methods, incipient wet impregnation and ultrasound impregnation method. In this paper, we study the effect of Au addition using the recharge method on NiW nanomaterials supported on mixed oxides on the physicochemical properties of synthesized nanomaterials. The prepared nanomaterials were characterized by scanning electron microscopy, BET specific surface area, X-ray diffraction, diffuse reflectance spectroscopy in the UV–visible range and temperature-programmed desorption of hydrogen. The experimental results showed that after loading of gold, the dispersion was higher (46% and 50%) with the trimetallic nanomaterials synthesized by incipient wet impregnation plus recharge method than with impregnation plus ultrasound recharge method, indicating a greater number of active trimetallic (NiWAu) sites in these materials. Small-sized Au from NiWAu/ACTU1 trimetallic nanostructures was enlarged for NiWAu/ACT1. The strong metal NPs–support interaction shown for the formation of NiAl2O4, Ni-W-O and Ni-Au-O species simultaneously present in the surface of trimetallic nanomaterial probably plays an important role in the degree of dispersion of the gold active phase.

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Preparation of catalyst as Au doped Mn1Co9Ox/ceramic system for total oxidation of CO

Vietnam Journal of Catalysis and Adsorption ◽

10.51316/jca.2021.066 ◽

2021 ◽

Vol 10 (4) ◽

pp. 39-45

Author(s):

Phuong Pham Thi Mai ◽

Hoan Nguyen Quoc ◽

Quan Do Quoc ◽

Hung Nguyen Thanh

Keyword(s):

Sol Gel ◽

Active Phase ◽

Catalyst System ◽

Oxidation Of Co ◽

Sem Images ◽

Total Oxidation ◽

Wet Impregnation ◽

Modern Analysis ◽

Catalyst Powder ◽

Xrd Patterns

In this paper, the Au doped Mn1Co9Ox was investigated for total oxidation of CO. The sol-gel method was applied to prepare this catalyst and some modern analysis methods as XRD, EPR, TPx, SEM were utilized to characterize its properties. The XRD patterns showed only Co3O4 phase without any peaks belonging to Mn or Au. However, the presence of Au and Mn was confirmed by EPR and O2-TPD results. With the aim to further apply catalyst in reality, the Au doped Mn1Co9Ox was deposited on ceramic by sol-gel, wet impregnation. The SEM images displayed the successful coating of active phase on substrate. However, the complete catalyst system didn’t have the high activity in total CO oxidation like the catalyst powder because of large agglomerations on coatings.

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TiO2 and N-TiO2 Sepiolite and Zeolite Composites for Photocatalytic Removal of Ofloxacin from Polluted Water

Materials ◽

10.3390/ma13030537 ◽

2020 ◽

Vol 13 (3) ◽

pp. 537 ◽

Cited By ~ 4

Author(s):

Michela Sturini ◽

Federica Maraschi ◽

Alice Cantalupi ◽

Luca Pretali ◽

Stefania Nicolis ◽

...

Keyword(s):

Diffuse Reflectance Spectroscopy ◽

Sol Gel ◽

Zeolite Catalysts ◽

Polluted Water ◽

X Ray Diffraction ◽

Direct Photolysis ◽

Drug Degradation ◽

Particle Dimension ◽

Photocatalytic Removal ◽

Tio2 Support

TiO2 sepiolite and zeolite composites, as well the corresponding N-doped composites, synthesized through a sol–gel method, were tested for the photocatalytic degradation of a widespread fluoroquinolone antibiotic (ofloxacin) under environmental conditions. The catalysts were characterized by X-ray diffraction (XRD), Brunauer–Emmett–Teller (BET), scanning electron microscopy (SEM), and diffuse reflectance spectroscopy (DRS) analyses. A complete drug degradation occurred in 10–15 min in the presence of both TiO2 sepiolite and zeolite catalysts, and in 20–30 min with the N-doped ones. Sepiolite proved to be a better TiO2 support compared to the most common zeolite both in terms of adsorption capacity and photocatalytic efficiency in pollutants degradation. The influence of nitrogen doping (red shift from 3.2 to 3.0 eV) was also investigated. Although it was blurred by a marked increase of the particle dimension and thus a decrease of the specific surface area of the doped catalysts, it allowed a faster drug removal than direct photolysis. The photochemical paths and photoproducts were investigated, too.

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Oxidative dehydrogenation of isobutane over supported V-Mo mixed oxides

Journal of the Serbian Chemical Society ◽

10.2298/jsc091204099m ◽

2010 ◽

Vol 75 (8) ◽

pp. 1115-1124 ◽

Cited By ~ 6

Author(s):

Gheorghiţa Mitran ◽

Ioan-Cezar Marcu ◽

Adriana Urdă ◽

Ioan Săndulescu

Keyword(s):

Oxidative Dehydrogenation ◽

Mixed Oxides ◽

Catalytic Performance ◽

Molybdenum Oxides ◽

Impregnation Method ◽

N2 Adsorption ◽

Wet Impregnation ◽

Vis Spectroscopy ◽

Wet Impregnation Method ◽

Oxidative Dehydrogenation Of Isobutane

Vanadium-molybdenum oxides supported on Al2O3, CeO2 and TiO2 were prepared by a ?wet? impregnation method, characterized using DRX, N2 adsorption, UV-Vis spectroscopy, electrical conductivity measurements and tested in the oxidative dehydrogenation of isobutane. The catalytic performance in the oxidative dehydrogenation of isobutane at 400-550?C depended on the nature of support and on the content of VMoO species on the support. The catalysts supported on alumina were more active and selective than those supported on ceria and titania.

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Synthesis and Characterization of MgO/MCM-22 as Catalytic Support Using the Impregnation Technique

Materials Science Forum ◽

10.4028/www.scientific.net/msf.881.41 ◽

2016 ◽

Vol 881 ◽

pp. 41-45

Author(s):

Caroline Vasconcelos Fernandes ◽

Vitória de Andrade Freire ◽

Bianca Viana de Sousa

Keyword(s):

Structural Changes ◽

Three Dimensional ◽

Impregnation Method ◽

Wet Impregnation ◽

Catalytic Support ◽

Impregnation Technique ◽

Xrd Patterns ◽

Metal Incorporation ◽

Wet Impregnation Method

MCM-22 is a microporous molecular sieve with a system of sinusoidal three-dimensional channels that do not interconnect themselves, which presents good adsorption capacity and high acidity. Thus, this study aims to evaluate the chemical and structural properties of the catalyst MgO/MCM-22 using wet impregnation method. The synthesis of the zeolite was performed using the static hydrothermal method. Through the XRD patterns, it was possible to observe that the metal incorporation process did not cause structural changes, as well as the analysis showed small peaks related to the magnesium oxide in the structure. The micrographs presented a spherical morphology with depression in the central region. FTIR spectra showed the typical peaks of metal with little differences in the typical peaks of MCM-22.

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An overview of the synthesis of CuO-ZnO nanocomposite for environmental and other applications

Nanotechnology Reviews ◽

10.1515/ntrev-2017-0144 ◽

2018 ◽

Vol 7 (3) ◽

pp. 267-282 ◽

Cited By ~ 22

Author(s):

Susmita Das ◽

Vimal Chandra Srivastava

Keyword(s):

Metal Oxide ◽

Environmental Science ◽

Mixed Oxides ◽

Sol Gel ◽

Metal Oxide Semiconductor ◽

Oxide Semiconductor ◽

Wet Impregnation ◽

Practical Applications ◽

Wide Range ◽

Co Precipitation

Abstract In the field of environmental science, metal oxide nanocomposites have gained a great attention for both theoretical and experimental aspects of their upgradation because of their wide range of practical applications such as catalysts, sensors, hydrogen storages, and optoelectronics. Among all nanocomposites, Copper oxide-zinc oxide (CuO-ZnO) has attracted more research due to their excellent tunable catalytic, electrical, optical, and magnetic properties and environment-friendly nature. Coupling of one metal oxide semiconductor with another metal oxide semiconductor produces an enlarged surface area, which provide more reactive sites, promotes mass transfer, promotes electron transfer, and avoids photo-corrosion of nanocomposites, which enhances its efficiency. The CuO-ZnO nanocomposite has been prepared by various methods such as co-precipitation, sol-gel, wet impregnation, and thermal decomposition. Depending on the preparation method and conditions used, different types of CuO-ZnO nanocomposites like Cu-doped ZnO, Cu supported/impregnated on ZnO, and CuO-ZnO mixed oxides with different morphologies of CuO-ZnO nanocomposites have been obtained. This article reviews the synthesis techniques of the CuO-ZnO nanocomposite and its morphology. Various practical applications of the CuO-ZnO nanocomposites have also been discussed.

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Photocatalytic Reduction of CO2 to Methanol Using the InVO4-Based Photocatalysts

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.396-398.2033 ◽

2011 ◽

Vol 396-398 ◽

pp. 2033-2037 ◽

Cited By ~ 5

Author(s):

Zhi Fang Jia ◽

Fu Min Wang ◽

Ying Bai ◽

Ning Liu

Keyword(s):

Metal Oxides ◽

Diffuse Reflectance Spectroscopy ◽

Photocatalytic Reduction ◽

Impregnation Method ◽

X Ray Diffraction ◽

Electron Hole ◽

Wet Impregnation ◽

X Ray ◽

Reduction Of Co2 ◽

Wet Impregnation Method

The InVO4-based photocatalysts loaded with metal oxides (Fe2O3, CuO, NiO) were synthesized by wet impregnation method. The prepared samples were characterized by X-ray diffraction (XRD), scanning electron microscopy(SEM), UV-vis diffuse reflectance spectroscopy(DRS). The influence of different metal oxides loading (Fe2O3, CuO, NiO) on the photocatalytic activity for photocatalytic reduction of CO2 was discussed. It is found that Fe2O3-loaded InVO4 significantly enhance the methanol yield through promoting the effective separation of photoinduced electron-hole pairs.

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Effect of Metal Loading in Unpromoted and Promoted CoMo/Al2O3–TiO2 Catalysts for the Hydrodeoxygenation of Phenol

Catalysts ◽

10.3390/catal9060550 ◽

2019 ◽

Vol 9 (6) ◽

pp. 550 ◽

Cited By ~ 2

Author(s):

J. Andrés Tavizón-Pozos ◽

Carlos E. Santolalla-Vargas ◽

Omar U. Valdés-Martínez ◽

José Antonio de los Reyes Heredia

Keyword(s):

Catalytic Activity ◽

Active Sites ◽

Mixed Oxides ◽

Batch Reactor ◽

Sol Gel ◽

Active Phase ◽

Catalytic Performance ◽

Octahedral Coordination ◽

Optimum Amount ◽

Co Concentration

This paper reports the effects of changes in the supported active phase concentration over titania containing mixed oxides catalysts for hydrodeoxygenation (HDO). Mo and CoMo supported on sol–gel Al2O3–TiO2 (Al/Ti = 2) were synthetized and tested for the HDO of phenol in a batch reactor at 5.5 MPa, 593 K, and 100 ppm S. Characterization results showed that the increase in Mo loading led to an increase in the amount of oxide Mo species with octahedral coordination (MoOh), which produced more active sites and augmented the catalytic activity. The study of the change of Co concentration allowed prototypes of the oxide species and their relationship with the CoMo/AT2 activity to be described. Catalysts were tested at four different Co/(Co + Mo) ratios. The results presented a correlation between the available fraction of CoOh and the catalytic performance. At low CoOh fractions (Co/(Co + Mo) = 0.1), Co could not promote all MoS2 slabs and metallic sites from this latter phase performed the reaction. Also, at high Co/(Co + Mo) ratios (0.3 and 0.4), there was a loss of Co species. The Co/(Co + Mo) = 0.2 ratio presented an optimum amount of available CoOh and catalytic activity since the XPS results indicated a higher concentration of the CoMoS phase than at a higher ratio.

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Cu-Mg-Fe-O-(Ce) Complex Oxides as Catalysts of Selective Catalytic Oxidation of Ammonia to Dinitrogen (NH3-SCO)

Catalysts ◽

10.3390/catal10020153 ◽

2020 ◽

Vol 10 (2) ◽

pp. 153 ◽

Cited By ~ 2

Author(s):

Sylwia Górecka ◽

Kateřina Pacultová ◽

Kamil Górecki ◽

Aneta Smýkalová ◽

Katarzyna Pamin ◽

...

Keyword(s):

Catalytic Oxidation ◽

Diffuse Reflectance Spectroscopy ◽

Nitrogen Adsorption ◽

Active Phase ◽

Impregnation Method ◽

Oxide Systems ◽

Selective Catalytic Oxidation ◽

Direct Band ◽

Temperature Programmed ◽

Oxidation Of Ammonia

Multicomponent oxide systems 800-Cu-Mg-Fe-O and 800-Cu-Mg-Fe-O-Ce were tested as catalysts of selective catalytic oxidation of ammonia to dinitrogen (NH3-SCO) process. Materials were obtained by calcination of hydrotalcite-like compounds at temperature 800 °C. Some catalysts were doped with cerium by the wet impregnation method. Not only simple oxides, but also complex spinel-like phases were formed during calcination. The influence of chemical composition, especially the occurrence of spinel phases, copper loading and impregnation by cerium, were investigated. Materials were characterized by several techniques: X-ray diffraction (XRD), Fourier-transform infrared spectroscopy (FT-IR), low-temperature nitrogen adsorption (BET), cyclic voltammetry (CV), temperature programmed reduction (H2-TPR), UV-vis diffuse reflectance spectroscopy and scanning electron microscopy (SEM). Examined oxides were found to be active as catalysts of selective catalytic oxidation of ammonia with high selectivity to N2 at temperatures above 300 °C. Catalysts with low copper amounts (up to 12 wt %) impregnated by Ce were slightly more active at lower temperatures (up to 350 °C) than non-impregnated samples. However, when an optimal amount of copper (12 wt %) was used, the presence of cerium did not affect catalytic properties. Copper overloading caused a rearrangement of present phases accompanied by the steep changes in reducibility, specific surface area, direct band gap, crystallinity, dispersion of CuO active phase and Cu2+ accessibility leading to the decrease in catalytic activity.

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Catalytic Behaviour of Ce-Doped Ni Systems Supported on Stabilized Zirconia under Dry Reforming Conditions

Catalysts ◽

10.3390/catal9050473 ◽

2019 ◽

Vol 9 (5) ◽

pp. 473 ◽

Cited By ~ 7

Author(s):

Ahmed Sadeq Al-Fatesh ◽

Yasir Arafat ◽

Ahmed Aidid Ibrahim ◽

Samsudeen Olajide Kasim ◽

Abdulrahman Alharthi ◽

...

Keyword(s):

Catalytic Properties ◽

Active Phase ◽

Impregnation Method ◽

Co2 Reforming ◽

Wet Impregnation ◽

Zro2 Phase ◽

Physico Chemical ◽

Catalytic Behaviour ◽

Wet Impregnation Method ◽

Peculiar Behavior

Ni supported on bare and modified ZrO2 samples were synthesized using the incipient wet impregnation method. The t-ZrO2 phase was stabilized by incorporation of La2O3 into ZrO2. Moreover, the influence of CeO2-doping on the physico-chemical and catalytic properties under CO2 reforming conditions was probed. The characterization data of the investigated catalysts were obtained by using XRD, CO2/H2-TPD, BET, TPR, TPO, TGA, XPS and TEM characterization techniques. In the pristine Ni/Zr catalyst, the t-ZrO2 phase transformed into the monoclinic phase. However, upon support modification by La2O3, significant effects on the physicochemical properties were observed due to the monoclinic-to-tetragonal ZrO2 phase transformation also affecting the catalytic activity. As a result, superior activity on the La2O3 modified Ni/Zr catalyst was achieved, while no relevant change in the surface properties and activity of the catalysts was detected after doping by CeO2. The peculiar behavior of the Ni/La-ZrO2 sample was related to higher dispersion of the active phase, with a more pronounced stabilization of the t-ZrO2 phase.

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Preparation and Photocatalytic Activity of Fe-Ce-N Tri-Doped TiO2 Catalysts

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.750-752.1276 ◽

2013 ◽

Vol 750-752 ◽

pp. 1276-1282

Author(s):

Yao Yao Wang ◽

Hong Xie ◽

Wei Zhang ◽

Yu Bin Tang ◽

Fang Yan Chen

Keyword(s):

Photocatalytic Activity ◽

Diffuse Reflectance Spectroscopy ◽

Uv Light ◽

Anatase Phase ◽

Sol Gel ◽

Synergetic Effect ◽

Tetrabutyl Titanate ◽

Visible Range ◽

Doping Amount ◽

Optimal Doping

Fe-Ce-N tri-doped TiO2 photocatalyst was prepared by sol-gel method using tetrabutyl titanate as precursor. The optimal doping amount and calcinations temperature were determined. The prepared catalyst was characterized by X-ray diffraction (XRD) and UV-Vis diffuse reflectance spectroscopy, and the photocatalytic activity was evaluated by means of the degradation for methyl orange (MO) under UV light and daylight irradiation. The results indicated that the optimal doping amount was 1.0% N, 0.25% Fe and 0.05% Ce, and the appropriate calcination temperature was 400°C. XRD analysis showed that TiO2 existed in anatase phase completely. UV-Vis adsorption spectrum showed that Fe-Ce-N tri-doping resulted in a intense adsorption in the near UV and visible-light region and a red shift in the adsorption edge from UV range to visible range of 400-500nm. The photocatalytic activity of Fe-Ce-N tri-doped TiO2 under UV and daylight irradiation was very higher than that of bi-doped Fe-Ce-TiO2, Fe-N-TiO2, Ce-N-TiO2 and undoped TiO2. The significantly higher activity of Fe-Ce-N tri-doped TiO2 may be due to the synergetic effect of Fe, Ce and N in the tri-coped TiO2.

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