scholarly journals Influence of the Reduction Temperature and the Nature of the Support on the Performance of Zirconia and Alumina-Supported Pt Catalysts for n-Dodecane Hydroisomerization

Catalysts ◽  
2021 ◽  
Vol 11 (1) ◽  
pp. 88
Author(s):  
Diana García-Pérez ◽  
Maria Consuelo Alvarez-Galvan ◽  
Jose M. Campos-Martin ◽  
Jose L. G. Fierro
Keyword(s):  
Catalytic Activity ◽  
Surface Area ◽  
Catalytic Properties ◽  
Catalytic Performance ◽  
Major Influence ◽  
Pt Catalysts ◽  
Reduction Temperature ◽  
Metal Dispersion ◽  
Tungsten Oxides ◽  
Supported Pt Catalysts

Catalysts based on zirconia- and alumina-supported tungsten oxides (15 wt % W) with a small loading of platinum (0.3 wt % Pt) were selected to study the influence of the reduction temperature and the nature of the support on the hydroisomerization of n-dodecane. The reduction temperature has a major influence on metal dispersion, which impacts the catalytic activity. In addition, alumina and zirconia supports show different catalytic properties (mainly acid site strength and surface area), which play an important role in the conversion. The NH3-TPD profiles indicate that the acidity in alumina-based catalysts is clearly higher than that in their zirconia counterparts; this acidity can be attributed to a stronger interaction of the WOx species with alumina. The PtW/Al catalyst was found to exhibit the best catalytic performance for the hydroisomerization of n-dodecane based on its higher acidity, which was ascribed to its larger surface area relative to that of its zirconia counterparts. The selectivity for different hydrocarbons (C7–10, C11 and i-C12) was very similar for all the catalysts studied, with branched C12 hydrocarbons being the main products obtained (~80%). The temperature of 350 °C was clearly the best reduction temperature for all the catalysts studied in a trickled-bed-mode reactor.

Effect of Silica Promoter on Performance of CuO-ZnO-ZrO2 Catalyst for Methanol Synthesis from CO2 Hydrogenation

2014 ◽  
Vol 556-562 ◽  
pp. 117-122 ◽  
Author(s):  
Miao Yao Jia ◽  
Wen Gui Gao ◽  
Hua Wang ◽  
Yu Hao Wang
Keyword(s):  
Catalytic Activity ◽  
Specific Surface ◽  
Surface Area ◽  
Methanol Synthesis ◽  
Catalytic Properties ◽  
Catalytic Performance ◽  
Precipitation Method ◽  
Test Results ◽  
Excellent Performance ◽  
Co Precipitation

Various CuO-ZnO-ZrO2(CZZ) catalysts for methanol synthesis from CO2 hydrogenation were prepared by co-precipitation method. Small amount of silica was incorporated into CZZ catalyst to produce these modified ternary CZZ catalysts. The effects of silica on physicochemical and catalytic properties were studied by TG-DTG,XRD,BET,N2O chemisorption,H2-TPR,NH3-TPD and CO2-TPD techniques. The results show that the properties of catalysts were strongly influenced by the content of SiO2 used as promoter. The catalytic performance for methanol synthesis from CO2 hydrogenation was evaluated. The test results show that the CZZ catalyst modified with 4 wt.% SiO2 exhibits an optimum catalytic activity. The silica improves the dispersion of CuO and its modified CZZ catalysts exhibits higher specific surface area, which were confirmed to be responsible for excellent performance of the catalysts for methanol synthesis from CO2 hydrogenation.

Investigation of CuMnOx spinel catalyst for toluene oxidation

2021 ◽  
Vol 10 (4) ◽  
pp. 52-58
Author(s):  
Hien Tran Thị Thu ◽  
Thuy Ly Bich ◽  
Phuong Pham Thi Mai ◽  
Thang Le Minh
Keyword(s):  
Catalytic Activity ◽  
Specific Surface ◽  
Surface Area ◽  
Specific Surface Area ◽  
Sol Gel ◽  
Catalytic Performance ◽  
Reduction Temperature ◽  
Gel Method ◽  
Oxygen Conditions ◽  
Reduction Capacity

CuMnOx spinel catalyst, prepared by the sol-gel method, and characterized by modern techniques such as XRD, BET, H2-TPR, EPR, were used to oxide toluene in the temperature range from 150oC to 400oC . Among,  the investigated catalysts as MnO2, CuO, and CuMnOx, the CuMnOx showed the highest catalytic activity. It converted 100% toluene to CO2 at 250oC in excessed oxygen conditions. The higher catalytic performance of CuMnOx than MnO2, CuO because of its higher specific surface area and its lower reduction temperature. The results also implied that the interaction between Cu and Mn could improve the reduction capacity of CuMnOx catalyst. In summary, the CuMnOx catalyst is a promising catalyst for toluene treatment.

A mesoporous “shell-in-shell” structured nanocatalyst with large surface area, enhanced synergy, and improved catalytic performance for Suzuki–Miyaura coupling reaction

2014 ◽  
Vol 50 (82) ◽  
pp. 12356-12359 ◽  
Author(s):  
Baocang Liu ◽  
Yuefang Niu ◽  
Yan Li ◽  
Fan Yang ◽  
Jiamin Guo ◽  
...  
Keyword(s):  
Catalytic Activity ◽  
Surface Area ◽  
Coupling Reaction ◽  
Catalytic Performance ◽  
Large Surface Area ◽  
Mesoporous Shell

A novel mesoporous “shell-in-shell” structured nanoreactor (@Pd/meso-TiO2/Pd@meso-SiO2) shows superior catalytic activity, stability, and selectivity for Suzuki–Miyaura coupling reaction.

Low-Temperature Water–Gas Shift: Effects of Y and Na in High Surface Area Na-Doped, YSZ-Supported Pt Catalysts

2016 ◽  
pp. 309-326
Author(s):  
Michela Martinelli ◽  
Gary Jacobs ◽  
Uschi Graham ◽  
Wilson Shafer ◽  
Carlo Visconti ◽  
...  
Keyword(s):  
Low Temperature ◽  
Surface Area ◽  
High Surface ◽  
High Surface Area ◽  
Water Gas Shift ◽  
Pt Catalysts ◽  
Supported Pt Catalysts ◽  
Water Gas ◽  
Temperature Water

Remarkable promoting effects of BiOCl on the room-temperature selective oxidation of benzyl alcohol over supported Pt catalysts

2018 ◽  
Vol 42 (11) ◽  
pp. 8979-8984 ◽  
Author(s):  
Juanjuan Liu ◽  
Feng Han ◽  
Lingze Chen ◽  
Linfang Lu ◽  
Shihui Zou ◽  
...  
Keyword(s):  
Benzyl Alcohol ◽  
Selective Oxidation ◽  
Room Temperature ◽  
Catalytic Performance ◽  
Pt Catalysts ◽  
Oxidation Of Benzyl Alcohol ◽  
Supported Pt Catalysts

BiOCl, in addition to traditional Bi metal, could remarkably promote the catalytic performance of Pt/MOx in the selective oxidation of benzyl alcohol.

Catalytic Properties of Ni/CNTs and Ca-Promoted Ni/CNTs for Methanation Reaction of Carbon Dioxide

2014 ◽  
Vol 924 ◽  
pp. 217-226 ◽  
Author(s):  
Xiang Feng Hu ◽  
Wen Yang ◽  
Ning Wang ◽  
Shi Zhong Luo ◽  
Wei Chu
Keyword(s):  
Carbon Dioxide ◽  
Carbon Nanotubes ◽  
Catalytic Activity ◽  
Catalytic Properties ◽  
Supported Catalyst ◽  
Catalytic Performance ◽  
Impregnation Method ◽  
Methanation Reaction ◽  
Ni Species ◽  
Nickel Species

Nickel/carbon nanotubes (Ni/CNTs), Nickel/alumina (Ni/Al2O3), calcium-promoted Ni/CNTs and calcium-promoted Ni/Al2O3 were synthesized by impregnation method. Methanation of carbon dioxide was used as a probe to evaluate their catalytic performance. The features of these Ni-based catalysts were investigated via XRD, H2-TPR, H2-TPD and the N2 adsorptiondesorption isotherms. H2-TPR showed that nickel species on Ni/CNTs was reduced more easily with respect to that on Ni/Al2O3, and addition of Ca can increase the content of easily reducible Ni species for Ni/CNTs. XRD and H2-TPD indicated that addition of Ca promoted dispersion for CNTs-supported catalyst. These finding ultimately enhanced catalytic activity and stability for Ni/CNTs catalyst modified with Ca.

scholarly journals Surface and Catalytic Properties of γ-Irradiated Cr2O3/Al2O3 Solids

1997 ◽  
Vol 15 (6) ◽  
pp. 465-476 ◽  
Author(s):  
G.A. El-Shobaky ◽  
A.M. Ghozza ◽  
G.M. Mohamed
Keyword(s):  
Catalytic Activity ◽  
Co Oxidation ◽  
Surface Area ◽  
Pore Volume ◽  
Active Sites ◽  
Catalytic Properties ◽  
Total Pore Volume ◽  
Bet Surface Area ◽  
Two Samples ◽  
Γ Rays

Two samples of Cr2O3/Al2O3 were prepared by mixing a known mass of finely powdered Al(OH)3 with a calculated amount of CrO3 solid followed by drying at 120°C and calcination at 400°C. The amounts of chromium oxide employed were 5.66 and 20 mol% Cr2O3, respectively. The calcined solid specimens were then treated with different doses of γ-rays (20–160 Mrad). The surface and catalytic properties of the different irradiated solids were investigated using nitrogen adsorption at −196°C and the catalysis of CO oxidation by O2 at 300–400°C. The results revealed that γ-rays brought about a slight decrease in the BET surface area, SBET (15%), and in the total pore volume, Vp (20%), of the adsorbent containing 5.66 mol% Cr2O3. The same treatment increased the total pore volume, Vp (36%), and the mean pore radius, r̄ (43%), of the other adsorbent sample without changing its BET surface area. The catalytic activities of both catalyst samples were found to increase as a function of dose, reaching a maximum value at 80–160 Mrad and 40 Mrad for the solids containing 5.66 and 20 mol% Cr2O3, respectively. The maximum increase in the catalytic activity measured at 300°C was 59% and 100% for the first and second catalyst samples, respectively. The induced effect of γ-irradiation on the catalytic activity was an increase in the concentration of catalytically active sites taking part in chemisorption and in the catalysis of CO oxidation by O2 without changing their energetic nature. This was achieved by a progressive removal of surface hydroxy groups during the irradiation process.

scholarly journals Metal Nanoparticles as Green Catalysts

Materials ◽  
2019 ◽  
Vol 12 (21) ◽  
pp. 3602 ◽  
Author(s):  
Neel Narayan ◽  
Ashokkumar Meiyazhagan ◽  
Robert Vajtai
Keyword(s):  
Catalytic Activity ◽  
Composite Materials ◽  
Green Synthesis ◽  
Metal Nanoparticles ◽  
Surface Area ◽  
Significant Role ◽  
High Surface ◽  
High Surface Area ◽  
Catalytic Performance ◽  
Materials Development

Nanoparticles play a significant role in various fields ranging from electronics to composite materials development. Among them, metal nanoparticles have attracted much attention in recent decades due to their high surface area, selectivity, tunable morphologies, and remarkable catalytic activity. In this review, we discuss various possibilities for the synthesis of different metal nanoparticles; specifically, we address some of the green synthesis approaches. In the second part of the paper, we review the catalytic performance of the most commonly used metal nanoparticles and we explore a few roadblocks to the commercialization of the developed metal nanoparticles as efficient catalysts.

Large-scale and facile synthesis of a porous high-entropy alloy CrMnFeCoNi as an efficient catalyst

2020 ◽  
Vol 8 (35) ◽  
pp. 18318-18326 ◽  
Author(s):  
Hailong Peng ◽  
Yangcenzi Xie ◽  
Zicheng Xie ◽  
Yunfeng Wu ◽  
Wenkun Zhu ◽  
...  
Keyword(s):  
Catalytic Activity ◽  
Surface Area ◽  
Large Scale ◽  
High Surface ◽  
High Surface Area ◽  
Catalytic Performance ◽  
High Entropy Alloy ◽  
Facile Synthesis ◽  
Efficient Catalyst ◽  
High Entropy

Porous high entropy alloy CrMnFeCoNi exhibited remarkable catalytic activity and stability toward p-nitrophenol hydrogenation. The enhanced catalytic performance not only resulted from the high surface area, but also from exposed high-index facets with terraces.

Effect of Pt Dispersion on the Catalytic Activity of Supported Pt Catalysts for Diesel Hydrocarbon Oxidation

2013 ◽  
Vol 56 (1-8) ◽  
pp. 249-254 ◽  
Author(s):  
Masaaki Haneda ◽  
Motoi Sasaki ◽  
Hideaki Hamada ◽  
Masakuni Ozawa
Keyword(s):  
Catalytic Activity ◽  
Hydrocarbon Oxidation ◽  
Pt Catalysts ◽  
Supported Pt Catalysts
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