Effect of preparation method and reaction parameters on catalytic activity for ammonia synthesis

2021 ◽  
Author(s):  
Rahat Javaid ◽  
Tetsuya Nanba
Keyword(s):  
Catalytic Activity ◽  
Preparation Method ◽  
Ammonia Synthesis ◽  
Reaction Parameters

The effect of reaction parameters on catalytic activity in the polymerization of ethylene using supported and unsupported metallocene catalysts

1998 ◽  
Vol 166 (1) ◽  
pp. 207-213 ◽  
Author(s):  
Raúl Quijada ◽  
René Rojas ◽  
Ana Narvaez ◽  
Luis Alzamora ◽  
Jaime Retuert ◽  
...  
Keyword(s):  
Catalytic Activity ◽  
Metallocene Catalysts ◽  
Reaction Parameters

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 Chromium-modified cobalt molybdenum nitrides as catalysts for ammonia synthesis

2019 ◽  
Vol 17 (1) ◽  
pp. 127-131
Author(s):  
Paweł Adamski ◽  
Marlena Nadziejko ◽  
Agata Komorowska ◽  
Adam Sarnecki ◽  
Aleksander Albrecht ◽  
...  
Keyword(s):  
Catalytic Activity ◽  
Specific Surface ◽  
Surface Area ◽  
Chromium Content ◽  
Ammonia Synthesis ◽  
Chromium Concentration ◽  
Synthesis Process ◽  
Pure Cobalt ◽  
Molybdenum Nitrides ◽  
Chromium Compounds

AbstractThe influence of chromium compounds on the properties of cobalt molybdenum nitrides was studied. CoMoO4 obtained by precipitation from cobalt and molybdenum salts was modified by the addition of chromium(III) nitrate. A mixture of cobalt-molybdenum nitrides, Co2Mo3N and Co3Mo3N, was formed by ammonolysis of modified CoMoO4. The concentration of Co2Mo3N decreases with increasing chromium content. The specific surface area of cobalt molybdenum nitrides consisting of 2 wt% of Cr atoms increased by 50% in comparison to pure cobalt molybdenum nitrides. The catalytic activity of obtained catalysts in ammonia synthesis process decreases with rising of chromium concentration.

scholarly journals Hydrothermal Catalytic Conversion of Glucose into Lactic Acid with Acidic MIL-101(Fe)

2020 ◽  
Vol 2020 ◽  
pp. 1-7
Author(s):  
Xiaofang Liu ◽  
Zhigang Liu ◽  
Qiuyun Zhang ◽  
Hongguo Wu ◽  
Rui Wang
Keyword(s):  
Catalytic Activity ◽  
Lactic Acid ◽  
Reaction Time ◽  
Specific Surface ◽  
Catalytic Conversion ◽  
Temperature Reaction ◽  
Reaction Parameters ◽  
Acid Properties ◽  
Catalyst Reusability ◽  
First Time

MIL-101(Fe) was explored for the first time for the catalytic conversion of glucose into lactic acid (LA). The as-synthesized MIL-101(Fe) was successfully characterized, and its higher specific surface area, porosity, and feasible acid properties were confirmed to determine the remarkable catalytic activity in glucose-to-LA conversion (up to 25.4% yield) compared with other catalysts like MIL-101(Cr, Al) and UiO-66(Zr). The reaction parameters including temperature, reaction time, and substrate species as well as catalyst reusability were discussed.

Improved stability and activity of Fe-based catalysts through strong metal support interactions due to extrinsic oxygen vacancies in Ce0.8Sm0.2O2−δ for the efficient synthesis of ammonia

2020 ◽  
Vol 8 (32) ◽  
pp. 16676-16689 ◽  
Author(s):  
John Humphreys ◽  
Rong Lan ◽  
Shigang Chen ◽  
Shanwen Tao
Keyword(s):  
Catalytic Activity ◽  
Oxygen Vacancies ◽  
Ammonia Synthesis ◽  
Efficient Synthesis ◽  
Anion Vacancies ◽  
Metal Support ◽  
Improved Stability ◽  
Synthesis Catalysts ◽  
Metal Support Interactions

The SMSI between Fe and oxygen vacancies in Ce0.8Sm0.2O2−δ helps to weaken and break the strong NN bonds in N2, increasing the catalytic activity. Materials with anion vacancies improve oxygenate tolerance property of ammonia synthesis catalysts.

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.

Effect of the TiO2 crystal structure on the activity of TiO2-supported platinum catalysts for ammonia synthesis via the NO–CO–H2O reaction

2019 ◽  
Vol 9 (11) ◽  
pp. 2898-2905 ◽  
Author(s):  
Keisuke Kobayashi ◽  
Ryousuke Atsumi ◽  
Yuichi Manaka ◽  
Hideyuki Matsumoto ◽  
Tetsuya Nanba
Keyword(s):  
Crystal Structure ◽  
Catalytic Activity ◽  
Ammonia Synthesis ◽  
Platinum Catalysts ◽  
Supported Platinum ◽  
Supported Platinum Catalysts

The catalytic activity of Pt/TiO2 for ammonia synthesis via the NO–CO–H2O reaction is affected by the TiO2 crystal structure below 250 °C.

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