scholarly journals La2O3/CaO catalyst derived from eggshells: Effects of preparation method and La content on textural properties and catalytic activity for transesterification

2021 ◽  
Vol 149 ◽  
pp. 106247
Author(s):  
Kanokwan Ngaosuwan ◽  
Waranya Chaiyariyakul ◽  
Onjira Inthong ◽  
Worapon Kiatkittipong ◽  
Doonyapong Wongsawaeng ◽  
...  
Keyword(s):  
Catalytic Activity ◽  
Preparation Method ◽  
Textural Properties

Synthesis of Macro-Porous De-NOx Catalysts for Poly-Tetra-Fluoro-Ethylene Membrane Bag Filter

2021 ◽  
Vol 21 (8) ◽  
pp. 4537-4543
Author(s):  
Byung Chan Kwon ◽  
Dohyung Kang ◽  
Seung Woo Lee ◽  
No-Kuk Park ◽  
Jang Hun Lee ◽  
...  
Keyword(s):  
Catalytic Activity ◽  
Nitrogen Oxides ◽  
Porous Alumina ◽  
Combustion Process ◽  
Textural Properties ◽  
Filter Material ◽  
Facilitated Diffusion ◽  
Exhaust Gas ◽  
Bag Filter ◽  
Combustion Exhaust

This study examined the effects of the porosity of catalytic bag-filter materials for applications to the SNCR (selective noncatalytic reduction)-SCR (selective catalytic reduction) hybrid process for highly treating nitrogen Oxides (NOx) in the exhaust gas of a combustion process. A V2O5/TiO2 catalyst was dispersed in a PTFE (poly-tetra-fluoro-ethylene) used as the catalytic bag-filter material to remove particulate matter and nitrogen oxides contained in the combustion exhaust gas. Macroporous alumina was added into a V2O5/TiO2-dispersed PTFE to improve the catalytic activity of V2O5/TiO2 dispersed in the PTFE material. In this study, the textural properties and denitrification performances of the V2O5/TiO2-dispersed PTFE materials were examined according to the addition of macro-porous alumina. When the denitrification catalyst was solely dispersed in the PTFE material, the catalyst inside the PTFE backbone had low gas-solid contact efficiency owing to the low porosity of the PTFE materials, resulting in low denitrification efficiency. On the other hand, the catalytic activity of V2O5/TiO2 dispersed inside the macro-porous PTFE material was significantly enhanced by adding macro-porous alumina into the PTFE matrix. The enhanced textural properties of the macro-porous PTFE material where V2O5/TiO2 was uniformly dispersed proved the facilitated diffusion of combustion exhaust gas into the PTFE material.

The Effect of Ni Precursor Salts on Diatomite Supported Ni-Mg Catalysts in Methanation of CO2

2021 ◽  
Vol 1016 ◽  
pp. 1417-1422
Author(s):  
Chao Sun ◽  
Jugoslav Krstic ◽  
Vojkan Radonjic ◽  
Miroslav Stankovic ◽  
Patrick da Costa
Keyword(s):  
Catalytic Activity ◽  
Atmospheric Pressure ◽  
Textural Properties ◽  
Catalytic Performance ◽  
Nickel Salt ◽  
Nitrate Salt ◽  
Efficient Catalyst ◽  
Mild Conditions ◽  
The Difference ◽  
Supported Ni

This study is aimed to investigate the effect of Ni precursor salts on the properties (textural, phase-structural, reducibility, and basicity), and catalytic performance of diatomite supported Ni-Mg catalyst in methanation of CO2. The NiMg/D-X catalysts derived from various nickel salts (X = S-sulfamate, N-nitrate or A-acetate) were synthesized by the precipitation-deposition (PD) method. The catalysts were characterized by N2-physisorption, XRD, TPR-H2, and TPD-CO2 techniques. The different catalytic activity (conversion) and selectivity, observed in CO2 methanation carried out under relatively mild conditions (atmospheric pressure; temperatures: 250-450 °C) are related and explained by the difference in textural properties, metallic Ni-crystallite size, reducibility, and basicity of studied catalysts. The results showed that catalyst derived from Ni-nitrate salt (NiMg/D-N) is more suitable for the preparation of efficient catalyst for CO2 methanation than its counterparts derived from sulfamate (NiMg/D-S) or acetate (NiMg/D-A) nickel salt. The NiMg/D-N catalyst showed the highest specific surface area and total basicity, and the best catalytic performance with CO2 conversion of 63.3 % and CH4 selectivity of 80.9 % at 450 °C.

scholarly journals Facile Mechanochemical Synthesis of Nickel/Graphene Oxide Nanocomposites with Unique and Tunable Morphology: Applications in Heterogeneous Catalysis and Supercapacitors

Catalysts ◽  
2019 ◽  
Vol 9 (5) ◽  
pp. 486 ◽  
Author(s):  
Mayakrishnan Gopiraman ◽  
Somasundaram Saravanamoorthy ◽  
Dian Deng ◽  
Andivelu Ilangovan ◽  
Ick Soo Kim ◽  
...  
Keyword(s):  
Graphene Oxide ◽  
Catalytic Activity ◽  
Specific Capacitance ◽  
Preparation Method ◽  
High Rate ◽  
Ni Nanoparticles ◽  
Graphene Nanocomposites ◽  
Factual Content ◽  
Tunable Morphology ◽  
Defective Sites

In this study, a very simple and highly effective mechanochemical preparation method was developed for the preparation of Ni nanoparticles supported graphene oxide (GO) nanocomposites (Ni/GO, where Ni is a composition of Ni(OH)2, NiOOH, NiO, Ni2O3 and NiO2), 3 wt% NiO/GO (Ni/GO-1) and 8 wt% NiO/GO(Ni/GO-2). The developed method is not only very simple and efficient, but also, the morphology of Ni/GO nanocomposites can be tuned by simply varying the metal loading. Morphology and specific surface area of the resultant Ni/GO nanocomposites were investigated by mean of AFM, HR-TEM and BET. Chemical sate and factual content of Ni in Ni/GO-1 and Ni/GO-2, and the presence of defective sites in Ni-nanocomposites were investigated in detail. To our delight, the prepared Ni/GO-2 demonstrated superior catalytic activity toward the reduction of 2- and 4-nitrophenol in water with high rate constant (kapp) of 35.4 × 10−3 s−1. To the best of our knowledge, this is the best efficient Ni-based graphene nanocomposites for the reduction of 2- and 4-NP reported to date. The Ni/GO-1 and Ni/GO-2 demonstrated an excellent reusability; no loss in its catalytic activity was noticed, even after 10th cycle. Surprisingly the Ni/GO-2 as electrode material exhibited an excellent specific capacitance of 461 F/g in 6 M KOH at a scan rate of 5 mV. Moreover, the Ni/GO nanocomposites were found to possess poor electrical resistance and high stability (no significant change in the specific capacitance even after 1000 cycles).

scholarly journals Carbon-Supported Fe Catalysts forCO2Electroreduction to High-Added Value Products: A DEMS Study: Effect of the Functionalization of the Support

2011 ◽  
Vol 2011 ◽  
pp. 1-13 ◽  
Author(s):  
S. Pérez-Rodríguez ◽  
G. García ◽  
L. Calvillo ◽  
V. Celorrio ◽  
E. Pastor ◽  
...  
Keyword(s):  
Catalytic Activity ◽  
Ethylene Glycol ◽  
Surface Chemistry ◽  
Physicochemical Properties ◽  
Electrochemical Properties ◽  
Textural Properties ◽  
Carbon Support ◽  
Product Distribution ◽  
Added Value ◽  
Fe Catalysts

Vulcan XC-72R-supported Fe catalysts have been synthesised for the electroreduction of CO2to high-added value products. Catalysts were obtained by the polyol method, using ethylene glycol as solvent and reducing agent. Prior to the metal deposition, Vulcan was subjected to different oxidation treatments in order to modify its surface chemistry and study its influence on the physicochemical and electrochemical properties of the catalysts, as well as on the product distribution. The oxidation treatments of the supports modify their textural properties, but do not affect significantly the physicochemical properties of catalysts. However, DEMS studies showed that the carbon support degradation, the distribution of products, and the catalytic activity toward the CO2electroreduction reaction depend significantly on the surface chemistry of the carbon support.

scholarly journals Carbon Dioxide Reforming of Methane over Ni Supported SiO2: Influence of the Preparation Method on the Resulting Structural Properties and Catalytic Activity

Catalysts ◽  
2020 ◽  
Vol 10 (7) ◽  
pp. 795 ◽  
Author(s):  
Hua-Ping Ren ◽  
Shao-Peng Tian ◽  
Si-Yi Ding ◽  
Gui-Qiu Huang ◽  
Min Zhu ◽  
...  
Keyword(s):  
Carbon Dioxide ◽  
Particle Size ◽  
Catalytic Activity ◽  
Citric Acid ◽  
Preparation Method ◽  
Complexing Agents ◽  
Impregnation Method ◽  
Carbon Dioxide Reforming ◽  
Highly Active ◽  
Before And After

Ni-C/SiO2 and Ni-G/SiO2 catalysts were prepared by a complexed-impregnation method using citric acid and glycine as complexing agents, respectively. Ni/SiO2 was also prepared by the conventional incipient impregnation method. All the catalysts were comparatively tested for carbon dioxide reforming of methane (CDR) at P = 1.0 atm, T = 750 °C, CO2/CH4 = 1.0, and GHSV = 60,000 mL·g−1·h−1. The results showed that Ni-C/SiO2 and Ni-G/SiO2 exhibited better CDR performance, especially regarding stability, than Ni/SiO2. The conversions of CH4 and CO2 were kept constant above 82% and 87% after 20 h of reaction over Ni-C/SiO2 and Ni-G/SiO2 while they were decreased from 81% and 88% to 56% and 59%, respectively, over the Ni/SiO2. The characterization results of the catalysts before and after the reaction showed that the particle size and the distribution of Ni, as well as the interactions between Ni and the support were significantly influenced by the preparation method. As a result, an excellent resistance to the coking deposition and the anti-sintering of Ni was obtained over the Ni-C/SiO2 and Ni-G/SiO2, leading to a highly active and stable CDR performance.

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