scholarly journals Nanosheet-Like Ho2O3 and Sr-Ho2O3 Catalysts for Oxidative Coupling of Methane

Catalysts ◽  
2021 ◽  
Vol 11 (3) ◽  
pp. 388
Author(s):  
Yuqiao Fan ◽  
Changxi Miao ◽  
Yinghong Yue ◽  
Weiming Hua ◽  
Zi Gao
Keyword(s):  
Oxidative Coupling ◽  
Temperature Programmed Desorption ◽  
Oxidative Coupling Of Methane ◽  
Molar Ratio ◽  
Impregnation Method ◽  
Oxygen Species ◽  
N2 Adsorption ◽  
Basic Sites ◽  
Chemisorbed Oxygen ◽  
Temperature Programmed

In this work, Ho2O3 nanosheets were synthesized by a hydrothermal method. A series of Sr-modified Ho2O3 nanosheets (Sr-Ho2O3-NS) with a Sr/Ho molar ratio between 0.02 and 0.06 were prepared via an impregnation method. These catalysts were characterized by several techniques such as XRD, N2 adsorption, SEM, TEM, XPS, O2-TPD (temperature-programmed desorption), and CO2-TPD, and they were studied with respect to their performances in the oxidative coupling of methane (OCM). In contrast to Ho2O3 nanoparticles, Ho2O3 nanosheets display greater CH4 conversion and C2-C3 selectivity, which could be related to the preferentially exposed (222) facet on the surface of the latter catalyst. The incorporation of small amounts of Sr into Ho2O3 nanosheets leads to a higher ratio of (O− + O2−)/O2− as well as an enhanced amount of chemisorbed oxygen species and moderate basic sites, which in turn improves the OCM performance. The optimal catalytic behavior is achievable on the 0.04Sr-Ho2O3-NS catalyst with a Sr/Ho molar ratio of 0.04, which gives a 24.0% conversion of CH4 with 56.7% selectivity to C2-C3 at 650 °C. The C2-C3 yield is well correlated with the amount of moderate basic sites present on the catalysts.

Study on CO2 Hydrogenation to Ethylene with Iron-Based Catalyst

2013 ◽  
Vol 791-793 ◽  
pp. 112-115
Author(s):  
Chun Yan Su ◽  
Jian Qun Tan ◽  
Cheng Xue Wang
Keyword(s):  
Carbon Dioxide ◽  
Temperature Programmed Desorption ◽  
Molar Ratio ◽  
Impregnation Method ◽  
Active Components ◽  
Reaction Conditions ◽  
Reaction Pressure ◽  
Carbon Dioxide Hydrogenation ◽  
Iron Based ◽  
Temperature Programmed

Carbon dioxide hydrogenation to ethylene was investigated on Fe-Cu-K-Ce loading catalysts. These catalysts were prepared by impregnation method, and studied on the CO2conversion and the selectivity of ethylene. The proper carrier was obtained comparing with their catalytic activity. The loading contents of active components on carriers and reaction conditions were studied. Results show that the MgO-ZSM-5 are the best carrier, the content of Fe at 15% and the molar ratio of Fe: Cu: K: Ce with 100: 20: 8: 8 is better under the condition of reaction temperature and reaction pressure are 623K and 1.0Mpa respectively with CO2conversion of more than 60% and the selectivity of ethylene of more than 20%. The catalysts were characterized by CO2temperature-programmed desorption (CO2-TPD).

scholarly journals Influence of Co2 on the Catalytic Performance Of La2O3/CeO2 and CaO/CeO2 Catalysts in the Oxidative Coupling of Methane

2013 ◽  
Vol 15 (1) ◽  
pp. 22-26 ◽  
Author(s):  
Barbara Litawa ◽  
Piotr Michorczyk ◽  
Jan Ogonowski
Keyword(s):  
Oxidative Coupling ◽  
Methane Conversion ◽  
Catalytic Properties ◽  
Catalytic Performance ◽  
Negative Influence ◽  
Oxidative Coupling Of Methane ◽  
Oxygen Mixture ◽  
Impregnation Method ◽  
Promoting Effect ◽  
Conversion Of Methane

In this work the La2O3/CeO2 (33 mol % of La) and CaO/CeO2 (33 mol % of Ca) catalysts were prepared by the impregnation method and characterized by XRD and CO2-TPD. The catalytic properties of the catalysts were tested in the OCM process at 1073 K using the methane/oxygen mixture of the mole ratio 3.7 or 2.5 additionally containing CO2 and helium balance. It was found that in the presence of both catalysts an addition of CO2 enhances the selectivity to the ethylene and ethane and it does not have any negative influence on methane conversion. In the case of the CaO/CeO2 catalyst the promoting effect of CO2 was the highest. When the partial pressure of CO2 equals to 39 kPa the increase in selectivity from 36 to 41% was noted while the conversion of methane equal to 19.4-19.7 %.

Effect of Rice Husk Ash Based Silicon Dioxide on the Properties of SUZ-4 Zeolite

2017 ◽  
Vol 729 ◽  
pp. 24-29
Author(s):  
Thitipob Sirisoontornpanit ◽  
Atichat Wongkoblab ◽  
Supunnee Junpirom
Keyword(s):  
Silicon Dioxide ◽  
Rice Husk ◽  
Rice Husk Ash ◽  
Sol Gel ◽  
Hydrothermal Process ◽  
Temperature Programmed Desorption ◽  
Acid Sites ◽  
Weak Acid ◽  
Molar Ratio ◽  
Temperature Programmed

SUZ-4 zeolite was synthesized by the sol-gel technique, followed by hydrothermal process. The effect of the molar ratio of rice husk ash based silicon dioxide to silica solution was investigated. The synthesized zeolite was characterized by XRD, SEM, N2 adsorption and temperature programmed desorption. The results show that the SUZ-4 zeolite was formed for all investigated conditions. However, the formation of MER zeolite occurred as an impurity for the content of rice husk ash higher than 75%. A needle shape crystal with mainly microporous structure is the feature of synthesized SUZ-4 zeolite. The result of temperature programmed desorption indicated that the chemical surface property of obtained SUZ-4 zeolite was weak acid sites.

Synthesis of Light Olefins from CO2 Hydrogenation on Fe/ZSM-5 Catalyst

2013 ◽  
Vol 423-426 ◽  
pp. 463-466
Author(s):  
Lin Yang ◽  
Jing Li ◽  
Jian Xin Cao
Keyword(s):  
Calcination Temperature ◽  
Mineral Composition ◽  
Mass Concentration ◽  
Xrd Analysis ◽  
Temperature Programmed Desorption ◽  
Light Olefins ◽  
Ferric Nitrate ◽  
Impregnation Method ◽  
Temperature Programmed ◽  
Composition Changes

A Fe/ZSM-5 catalyst was prepared by impregnation method and evaluated in the synthesis of light olefins from CO2 hydrogenation. It is found that The conversion of CO2, the yield of light olefins and hydrocarbons content reach 82.42%, 12.65%, 0.4885mol respectively under the conditions as follow, mass concentration of ferric nitrate 9%, silica to alumina ratio 25, calcination temperature of the catalyst 500°C. By the studies of NH3 temperature programmed desorption, performance changes of the catalysts was analysis. A possible mechanism is proposed on the basis of mineral composition changes of Fe/ZSM-5 catalyst in the synthesis of light olefins through XRD analysis.

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