MICROPOROUS AND MESOPOROUS MATERIALS
·
2014
·
IF 3.209
Ben Qi,Lan-Lan Lou,Yanbing Wang,Kai Yu,Ying Yang,Shuangxi Liu
Manganese containing mesoporous materials Mn-MCM-41 were prepared by template-ion exchange (TIE), in situ reduction (ISR), direct hydrothermal (DHT) and wetness impregnation (WI) methods. The samples were characterized by XRD , N 2 adsorption–desorption, HR-TEM, TG, UV–Vis, H 2 -TPR and ESR techniques, which illustrated that the definite structure of the MCM-41 was retained after introducing Mn into MCM-41 by different method. The catalytic activity and selectivity of the Mn-MCM-41 in the epoxidation of styrene with 30% H 2 O 2 as an oxidant agent were explored. The TIE catalysts showed the highest activity but Mn 2+ was leached during the reaction. The ISR catalysts exhibited high activity for epoxidation of styrene. Furthermore, recycling studies proved the ISR catalysts as heterogeneous catalysts , which did not lose the catalytic activity after four recycles appreciably. However, the DHT and WI catalysts showed poor performance in the catalytic epoxidation of styrene. Various parameters such as different reaction molar ratio of H 2 O 2 /styrene, catalyst amount, and kinds of solvents were studied to optimize the reaction conditions.
研究领域:
催化化学
·
材料化学
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有机合成
·
多相催化
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环境友好氧化过程
✓ 已验证
DOI
高影响因子
TRANSACTIONS OF TIANJIN UNIVERSITY
·
2018
·Vol. 24
·期 4
·361-369
·
IF 0
Zhang Xubin,Dong Jianxin,Hao Zhencheng,Cai Wangfeng,Wang Fumin
Active Fe- and Mn-loaded MCM-41 (Fe–Mn/MCM-41), which was synthesized via a hydrothermal reaction followed by impregnation, is used in the heterogeneous Fenton reaction to degrade methyl orange (MO) in aqueous solution. The synthesized samples were characterized by X-ray diffraction, scanning electron microscopy, transmission electron microscopy, N 2 adsorption–desorption isotherm analysis, Fourier transform infrared spectroscopy, and X-ray photoelectron spectroscopy. Compared with Fe/MCM-41 and Mn/MCM-41, Fe–Mn/MCM-41 showed higher activity for MO degradation and mineralization. Effects of various operating parameters, such as pH, Mn content, and H 2 O 2 dosage, on the degradation process were subsequently investigated. Results of experiments on the effect of radical scavengers revealed that the degradation of MO could be attributed to oxidation by HO·. The synergy of Fe and Mn species in the Fenton oxidation process was also explained.
研究领域:
环境科学
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催化材料
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水处理技术
✓ 已验证
产品关联
DOI
Catalysts
·
2025
·Vol. 15
·期 6
·545
·
IF 4
Xiaohong Yao,Jian Zhang,Chao Long
This study explored how pore size engineering in Nb-Mn/MCM-41 catalysts affects plasma-catalytic toluene oxidation. Adjusting the pore diameter (2.49–3.98 nm) modulated metal-support interactions and oxygen dynamics, with pore expansion to 3.73 nm (M3) optimizing the Mn4+/(Mn2++ Mn3+) ratio (XPS: 36.8%), the amount of lattice oxygen species (O2-TPD: 0.222 mmol/g), and crystallite size control (1.5 ± 0.2 nm, TEM). Smaller pores (M1: 2.49 nm) enhanced toluene adsorption but limited active site accessibility, while oversized pores (M4: 3.98 nm) reduced oxygen storage capacity (0.600→0.412 mmol/g). The Nb-Mn/M3 catalyst achieved superior performance with 96.8% toluene conversion, 55.0% CO2selectivity, and 85.4% carbon balance, while minimizing organic byproducts (GC-MS). Mechanistic studies revealed pore-mediated oxygen storage-transport cycles as critical for decoupling adsorption and oxidation steps. This study reveals fundamental mechanisms linking pore architecture to plasma-catalytic synergy in toluene oxidation, offering critical insights for the systematic design of energy-efficient, plasma-catalytic systems targeting industrial VOCs remediation.
研究领域:
催化化学
·
环境化学
·
材料科学
·
等离子体化学
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纳米技术
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表面科学
✓ 已验证
产品关联
DOI
高影响因子
SEPARATION AND PURIFICATION TECHNOLOGY
·
2020
·
IF 5.774
Xiao Zhang,Bin Ren,Yanhua Xu,Xi Li,Peng Yu,Yongjun Sun,Huaili Zheng
Mn/MCM-41 and imp-Mn/MCM-41 catalysts were prepared in this study through metal heteroatom substitution and impregnation methods, respectively, and their catalytic oxidation performance of toluene under non-thermal plasma (NTP) in a dielectric barrier discharge reactor was studied. The stability of the catalyst and the parameters of catalytic oxidation conditions (initial concentration of toluene, O 2 ratio, and relative humidity of carrier gas) were optimized. Characterization proved that the impregnation method resulted in the existence of manganese in the form of oxides (MnO 2 , Mn 2 O 3 ) outside the pores of MCM-41. Meanwhile, the metal heteroatom substitution method implanted manganese into the mesoporous structure and replaced part of it with Si-O-Mn. NTP catalytic oxidation of toluene, ozone emission, and GC–MS by-product analysis confirmed that 60Mn/MCM-41 catalyst has high catalytic activity. Moreover, the catalyst affected the production of by-products. The stability test revealed that the 60Mn/MCM-41 catalyst still respectively reached 84.6% and 61% in the conversion of toluene and the selectivity of CO 2 under the SED of 558 J/L after 40 h discharge reaction.
研究领域:
环境科学
·
催化化学
✓ 已验证
产品关联
DOI
高影响因子
危险品化学品经营许可证（带存储）