Ti incorporation in MCM-41 mesoporous molecular sieves using hydrothermal synthesis
Shengping WANG, Changqing MA, Yun SHI, Xinbin MA
《化学科学与工程前沿（英文）》
2014年
第8卷
第1期
页码 95-103
doi:
10.1007/s11705-014-1405-2
摘要：
Titanium-containing mesoporous materials (Ti-MCM-41) were obtained by hydrothermal synthesis. Such materials are active catalysts for the transesterification of dimethyl oxalate and phenol to produce diphenyl oxalate. To understand the role of the Ti in the catalytic process, Ti-MCM-41 samples with different Si/Ti ratios (from 5 to 100) were prepared and the samples were analyzed by Fourier transform infrared spectroscopy, UV-visible spectroscopy, and ammonia temperature programmed desorption. It was concluded that the Ti is incorporated into the framework of the MCM-41 and formed weak Lewis acid sites. In addition, the number of Ti(IV) sites increased as the amount of titanium increased. X-ray powder diffraction, N adsorption-desorption and transmission electron microscopy results showed that the Ti-MCM-41 samples have a hexagonal arrangement of mono-dimensional pores. A large number of Ti(IV) sites coupled with the mesoporous structure and large pore diameters are favorable for the transesterification catalytic properties of Ti-MCM-41.
关键词：
Ti-MCM-41
mesoporous molecular sieve
acid sites
transesterification
hydrothermal synthesis
Synthesis of nanofluids composed of deep eutectic solvents and metal-modified MCM-41 particles as multifunctional
《化学科学与工程前沿（英文）》
2023年
第17卷
第11期
页码 1776-1787
doi:
10.1007/s11705-023-2314-z
摘要：
Compared with traditional hydrodesulfurization, new nonhydrodesulfurization methods have the advantage of a high removal efficiency for thiophene compounds under mild conditions. However, independent nonhydrodesulfurization technologies are faced with their own shortcomings, such as limitations of the desulfurization performance and regeneration of materials. To overcome these limitations, four nanofluids were prepared by dispersing different metal-modified MCM-41 particles in deep eutectic solvent as multifunctional promoters to develop a comprehensive desulfurization method. Based on the excellent adsorbability and high catalytic activity of the dispersed particles and the outstanding extractability of deep eutectic solvent in nanofluids, a high sulfur removal of 99.33% was achieved for model oil under mild conditions in 15 min. The nanofluids also showed excellent reusability due to their high structural stability. In addition, NF@Cu/Al-MCM-41-2.5% exhibited the best desulfurization performance among the prepared nanofluids. This result was obtained because the introduction of Al ions increased the number of acid sites and defect sites to improve the catalytic activity and adsorbability, and the best affinity of Cu/Al-MCM-41 for the deep eutectic solvent favored the reaction mass transfer. This work opens the door to the development of a comprehensive nonhydrodesulfurization method based on the design of nanofluid materials.
关键词：
fuel oil desulfurization
nanofluids
catalytic ozonation
Atomistic simulations for adsorption and separation of flue gas in MFI zeolite and MFI/MCM-41 micro/mesoporous
Shengchi ZHUO, Yongmin HUANG, Jun HU, Honglai LIU
《化学科学与工程前沿（英文）》
2011年
第5卷
第2期
页码 264-273
doi:
10.1007/s11705-010-1007-6
摘要：
Adsorption of pure CO and N and separation of CO /N mixture in MFI zeolite and MFI/MCM-41 micro/mesoporous composite have been studied by using atomistic simulations. Fully atomistic models of MFI and MFI/MCM-41 are constructed and characterized. A bimodal pore size distribution is observed in MFI/MCM-41 from simulated small- and broad-angle X-ray diffraction patterns. The density of MFI/MCM-41 is lower than MFI, while its free volume and specific surface area are greater than MFI due to the presence of mesopores. CO is preferentially adsorbed than N , and thus, the loading and isosteric heat of CO are greater than N in both MFI and MFI/MCM-41. CO isotherm in MFI/MCM-41 is similar to that in MFI at low pressures, but resembles that in MCM-41 at high pressures. N shows similar amount of loading in MFI, MCM-41 and MFI/MCM-41. The selectivity of CO over N in the three adsorbents decreases in the order of MFI>MFI/MCM-41>MCM-41. With increasing pressure, the selectivity increases in MFI and MFI/MCM-41, but decreases in MCM-41. The self-diffusivity of CO and N in MFI decreases as loading increases, while in MFI/MCM-41, it first increases and then drops.
关键词：
adsorption
diffusion
CO2
flue gas
zeolite
micro/mesoporous composite
Preparation of TiO
Shenghung WANG, Kuohua WANG, Jihmirn JEHNG, Lichen LIU
《环境科学与工程前沿（英文）》
2012年
第6卷
第3期
页码 304-312
doi:
10.1007/s11783-010-0297-8
摘要：
Titanium dioxide is coated on the surface of MCM-41 wafer through the plasma enhanced chemical vapor deposition (PECVD) method using titanium isopropoxide (TTIP) as a precursor. Annealing temperature is a key factor affecting crystal phase of titanium dioxide. It will transform an amorphous structure to a polycrystalline structure by increasing temperature. The optimum anatase phase of TiO which can acquire the best methanol conversion under UV-light irradiation is obtained under an annealing temperature of 700°C for 2 h, substrate temperature of 500°C, 70 mL·min of oxygen flow rate, and 100 W of plasma power. In addition, the films are composed of an anatase-rutile mixed phase, and the ratio of anatase to rutile varies with substrate temperature and oxygen flow rate. The particle sizes of titanium dioxide are between 30.3 nm and 59.9 nm by the calculation of Scherrer equation. Under the reaction conditions of 116.8 mg·L methanol, 2.9 mg·L moisture, and 75°C of reaction temperature, the best conversion of methanol with UV-light is 48.2% by using the anatase-rutile (91.3/8.7) mixed phase TiO in a batch reactor for 60 min. While under fluorescent light irradiation, the best photoactivity appears by using the anatase-rutile (55.4/44.6) mixed phase TiO with a conversion of 40.0%.
关键词：
photocatalyst
titanium dioxide
MCM-41
plasma enhanced chemical vapor deposition (PECVD)
Synthesis, characterization and catalytic properties of mesoporous MCM-48 containing zeolite secondary
LI Qiang, ZHANG Ying, DOU Tao, LI Yuping, WANG Shan, SUN Famin
《化学科学与工程前沿（英文）》
2007年
第1卷
第1期
页码 1-5
doi:
10.1007/s11705-007-0001-0
摘要：
Mesoporous aluminosilicate MCM-48 containing zeolite secondary building units in the pore wall has been synthesized in alkaline media with a two-step procedure. The aluminosilicate precursors comprising zeolite secondary building units were first synthesized by carefully controlling reaction conditions and then were assembled using cotemplates of gemini surfactant [CHN(CH)(CH)N(CH)CH] (18-3-18) and triethanolamine (TEA). X-ray Diffraction (XRD) patterns of the as-made samples indicated that highly ordered mesostructured MCM-48 was formed. Transmission Electron Microscopy (TEM) images further verified the formation of MCM-48 with uniform cubic pore channel system having the pore opening diameter of about 25 Å. Compared with the conventionally synthesized MCM-48, the as-synthesized MCM-48 sample showed an adsorption band at 520 600 cm in its FT-IR spectrum, which was assigned to five-membered ring vibration from zeolite structure. This suggested the presence of zeolite building units in the pore wall. N2 adsorption data showed that the material had a much higher specific surface area (1 200 m/g) than the conventional MCM-48(1 100 m/g). Finally, the catalytic performance of the as-made MCM-48 was evaluated by hydrogenation dealkylation reaction of heavy aromatic hydrocarbons. Catalytic results showed that the as-made MCM-48 catalyst exhibited higher conversion than the conventional MCM-48 catalyst. The as-made mesostructured MCM-48 may have a potential catalytic application in the conversion of bulky molecules.
关键词：
diameter
mesostructured MCM-48
Catalytic
presence
five-membered
标题
作者
时间
类型
操作
Enhanced CuCl dispersion by regulating acidity of MCM-41 for catalytic oxycarbonylation of ethanol to
Pengzhen CHEN, Shouying HUANG, Jijie ZHANG, Shengping WANG, Xinbin MA
期刊论文
Ti incorporation in MCM-41 mesoporous molecular sieves using hydrothermal synthesis
Shengping WANG, Changqing MA, Yun SHI, Xinbin MA
期刊论文
Synthesis of nanofluids composed of deep eutectic solvents and metal-modified MCM-41 particles as multifunctional
期刊论文
Atomistic simulations for adsorption and separation of flue gas in MFI zeolite and MFI/MCM-41 micro/mesoporous
Shengchi ZHUO, Yongmin HUANG, Jun HU, Honglai LIU
期刊论文
Preparation of TiO
Shenghung WANG, Kuohua WANG, Jihmirn JEHNG, Lichen LIU
期刊论文
Synthesis, characterization and catalytic properties of mesoporous MCM-48 containing zeolite secondary
LI Qiang, ZHANG Ying, DOU Tao, LI Yuping, WANG Shan, SUN Famin
期刊论文
The synergic effects of highly selective bimetallic Pt-Pd/SAPO-41 catalysts for the
Guozhi Jia, Chunmu Guo, Wei Wang, Xuefeng Bai, Xiaomeng Wei, Xiaofang Su, Tong Li, Linfei Xiao, Wei Wu
期刊论文
基于LTCC技术与曲折线天线集成的封装天线系统
Gang DONG,Wei XIONG,Zhao-yao WU,Yin-tang YANG
期刊论文
Porous silica synthesis out of coal fly ash with no residue generation and complete silicon separation
期刊论文
基于LTCC技术集成曲折线天线的封装天线系统
Gang Dong, Wei Xiong, Zhao-yao Wu, Yin-tang Yang,gdong@mail.xidian.edu.cn
期刊论文
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