MCM-41

About: MCM-41 is a research topic. Over the lifetime, 2355 publications have been published within this topic receiving 91416 citations.

Ordered mesoporous molecular sieves synthesized by a liquid-crystal template mechanism

Abstract: MICROPOROUS and mesoporous inorganic solids (with pore diameters of ≤20 A and ∼20–500 A respectively)1 have found great utility as catalysts and sorption media because of their large internal surface area. Typical microporous materials are the crystalline framework solids, such as zeolites2, but the largest pore dimensions found so far are ∼10–12 A for some metallophosphates3–5 and ∼14 A for the mineral cacoxenite6. Examples of mesoporous solids include silicas7 and modified layered materials8–11, but these are invariably amorphous or paracrystalline, with pores that are irregularly spaced and broadly distributed in size8,12. Pore size can be controlled by intercalation of layered silicates with a surfactant species9,13, but the final product retains, in part, the layered nature of the precursor material. Here we report the synthesis of mesoporous solids from the calcination of aluminosilicate gels in the presence of surfactants. The material14,15 possesses regular arrays of uniform channels, the dimensions of which can be tailored (in the range 16 A to 100 A or more) through the choice of surfactant, auxiliary chemicals and reaction conditions. We propose that the formation of these materials takes place by means of a liquid-crystal 'templating' mechanism, in which the silicate material forms inorganic walls between ordered surfactant micelles.

Novel Polyethylenimine-Modified Mesoporous Molecular Sieve of MCM-41 Type as High-Capacity Adsorbent for CO2 Capture

Abstract: The objective of the work presented here is to develop a nanoporous solid adsorbent which can serve as a “molecular basket” for CO2 in the condensed form Polyethylenimine (PEI)-modified mesoporous molecular sieve of MCM-41 type (MCM-41-PEI) has been prepared and tested as a CO2 adsorbent The physical properties of the adsorbents were characterized by X-ray powder diffraction (XRD), N2 adsorption/desorption, and thermogravimetric analysis (TGA) The characterizations indicated that the structure of the MCM-41 was preserved after loading the PEI, and the PEI was uniformly dispersed into the channels of the molecular sieve The CO2 adsorption/desorption performance was tested in a flow system using a microbalance to track the weight change The mesoporous molecular sieve had a synergetic effect on the adsorption of CO2 by PEI A CO2 adsorption capacity as high as 215 mg-CO2/g-PEI was obtained with MCM-41-PEI-50 at 75 °C, which is 24 times higher than that of the MCM-41 and is even 2 times that of the pure

Synthesis of an ultralarge pore titanium silicate isomorphous to MCM-41 and its application as a catalyst for selective oxidation of hydrocarbons

Abstract: An ultralarge pore titanium silicate with MCM-41 structure has been prepared by direct hydrothermal synthesis; this material gives rise to useful catalysts for the selective oxidation of small and large organic compounds.