Insight into the Effect of Copper Substitution on the Catalytic Performance of LaCoO3-Based Catalysts for Direct Epoxidation of Propylene with Molecular Oxygen

2021 ◽  
Author(s):  
Jianyi Lei ◽  
Jiajun Dai ◽  
Kok Bing Tan ◽  
Jiale Huang ◽  
Guowu Zhan ◽  
...  
Keyword(s):  
Molecular Oxygen ◽  
Catalytic Performance ◽  
Epoxidation Of Propylene ◽  
Effect Of Copper ◽  
Copper Substitution ◽  
Insight Into

High Catalytic Performance of MoO3-Bi2SiO5/SiO2for the Gas-Phase Epoxidation of Propylene by Molecular Oxygen

ChemCatChem ◽  
2014 ◽  
Vol 6 (3) ◽  
pp. 876-884 ◽  
Author(s):  
Yijun Pang ◽  
Xiaohui Chen ◽  
Chengzhi Xu ◽  
Yangjun Lei ◽  
Kemei Wei
Keyword(s):  
Gas Phase ◽  
Molecular Oxygen ◽  
Catalytic Performance ◽  
Epoxidation Of Propylene

scholarly journals Insight into Active Centers and Anti-Coke Behavior of Niobium-Containing SBA-15 for Glycerol Dehydration

Catalysts ◽  
2021 ◽  
Vol 11 (4) ◽  
pp. 488
Author(s):  
Katarzyna Stawicka ◽  
Maciej Trejda ◽  
Maria Ziolek
Keyword(s):  
Coke Formation ◽  
Catalytic Performance ◽  
Acid Sites ◽  
Silica Matrix ◽  
High Concentration ◽  
Active Centers ◽  
Acidic Sites ◽  
Glycerol Dehydration ◽  
Adsorption Desorption ◽  
Insight Into

Niobium containing SBA-15 was prepared by two methods: impregnation with different amounts of ammonium niobate(V) oxalate (Nb-15/SBA-15 and Nb-25/SBA-15 containing 15 wt.% and 25 wt.% of Nb, respectively) and mixing of mesoporous silica with Nb2O5 followed by heating at 500 °C (Nb2O5/SBA-15). The use of these two procedures allowed obtaining materials with different textural/surface properties determined by N2 adsorption/desorption isotherms, XRD, UV-Vis, pyridine, and NO adsorption combined with FTIR spectroscopy. Nb2O5/SBA-15 contained exclusively crystalline Nb2O5 on the SBA-15 surface, whereas the materials prepared by impregnation had both metal oxide and niobium incorporated into the silica matrix. The niobium species localized in silica framework generated Brønsted (BAS) and Lewis (LAS) acid sites. The inclusion of niobium into SBA-15 skeleton was crucial for the achievement of high catalytic performance. The strongest BAS were on Nb-25/SBA-15, whereas the highest concentration of BAS and LAS was on Nb-15/SBA-15 surface. Nb2O5/SBA-15 material possessed only weak LAS and BAS. The presence of the strongest BAS (Nb-25/SBA-15) resulted in the highest dehydration activity, whereas a high concentration of BAS was unfavorable. Silylation of niobium catalysts prepared by impregnation reduced the number of acidic sites and significantly increased acrolein yield and selectivity (from ca. 43% selectivity for Nb-25/SBA-15 to ca. 61% for silylated sample). This was accompanied by a considerable decrease in coke formation (from 47% selectivity for Nb-25/SBA-15 to 27% for silylated material).

1,3-Butadiene production from aqueous ethanol over ZnO/MgO-SiO2 catalysts: Insight into H2O effect on catalytic performance

2021 ◽  
Vol 616 ◽  
pp. 118081
Author(s):  
Pavlo I. Kyriienko ◽  
Olga V. Larina ◽  
Dmytro Yu. Balakin ◽  
Anatolii O. Stetsuk ◽  
Yurii M. Nychiporuk ◽  
...  
Keyword(s):  
Aqueous Ethanol ◽  
Catalytic Performance ◽  
Insight Into

Phosphorus modified MoO3–Bi2SiO5/SiO2 catalyst for gas-phase epoxidation of propylene by molecular oxygen

2017 ◽  
Vol 43 (12) ◽  
pp. 7055-7071 ◽  
Author(s):  
Shengqiang Xu ◽  
Qingming Huang ◽  
Yanting Xu ◽  
Zhuoliang Ye ◽  
Xiaohui Chen
Keyword(s):  
Gas Phase ◽  
Molecular Oxygen ◽  
Epoxidation Of Propylene

MeAPO4 Berlinite as an Effective Catalyst for Mild Oxidation of Cyclohexane

2013 ◽  
Vol 709 ◽  
pp. 102-105 ◽  
Author(s):  
Da Lei Sun ◽  
Zi Sheng Chao
Keyword(s):  
Molecular Oxygen ◽  
Atmospheric Pressure ◽  
Molecular Sieve ◽  
Catalytic Performance ◽  
Synergic Effect ◽  
Mild Oxidation ◽  
Effective Catalyst ◽  
Ft Ir

Cobalt and/or manganese incorporated berlinites (CoMnAPO4) and aluminophosphate molecule sieve (CoMnAPO-5) were hydrothermally synthesized, characterized by XRD, FT-IR, XPS and SEM, and employed as catalysts in the oxidation of cyclohexane with molecular oxygen at 348 K under atmospheric pressure. It was found that the berlinite-based catalysts were more selective for the production of KA oil, stable during the reaction, but slightly less active for the conversion of cyclohexane, when compared to their molecular sieve counterparts. The CoMnAPO4exhibited a better catalytic performance, due to a synergic effect, than the CoAPO4or MnAPO4.

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