Investigation of the Structure of MCM‐41 Samples with a High Copper Content

Abstract

A series of MCM‐41s with a high copper content were synthesized at room temperature from sodium metasilicate (Na2SiO3) as the silicon source, tetraamminecopper(II) nitrate [Cu(NH3)4(NO3)2] as the copper source and cetyltrimethylammonium bromide (CTABr) as the template. The resulting material was characterized by using the following characterization techniques: X‐ray diffraction (XRD), N2‐adsorption isotherms, high‐resolution transmission electron microscopy (HRTEM), inductively coupled plasma (ICP), temperature‐programmed reduction (H2‐TPR), X‐ray photoelectron spectroscopy (XPS), Fourier‐transform infrared spectroscopy (FTIR), UV‐vis spectroscopy, electron‐spin resonance (ESR) and 29Si magic‐angle sample spinning nuclear magnetic resonance (MAS NMR) spectroscopy. The characterization techniques demonstrated the following: i) the copper atoms are incorporated into the framework of MCM‐41 and ii) the copper species in the samples are in a distorted octahedral coordination environment, with between four and six oxygen atoms in the first coordination sphere. The maximum copper content determined by ICP was 26 wt.‐% in the ordered mesoporous sample with a surface area of 525 m2 g–1 and an average pore diameter of 3.1 nm. The synthesized materials exhibited a high activity for nitrogen monoxide (NO) reduction by carbon monoxide (CO).

Synthesis, Characterization of Bimetallic V-Fe-SBA-15 and Its Catalytic Performance in the Hydroxylation of Phenol

“…The atomic weight of vanadium and iron were also greater than that of silicon, and which caused the increase of the reduced mass ( ). Hence, the vibration frequencies according to the formula = 1/2 c √ k/ decreased, and a similar phenomenon was observed and discussed by Kong et al 34 All these results suggested, in some extent, that the heteroatoms have been incorporated into the framework of SBA-15.…”

“…were used to estimate the incorporation of guest atoms in the mesoporous materials. 34 Some structure parameters of the samples were summarized in Table I. The increase of a 0 and D values could be taken as indication of the incorporation of the metals in the silica framework, probably due to the larger ion radii of V 5+ and Fe 3+ than that of Si 4+ .…”

CuO/SBA-15 materials synthesized by solid state grinding: Influence of CuO dispersion and multicycle operation on DeSO performances

“…Indeed, according to the literature, copper might be in strong interaction with the support as Cu-O-Si species which could explain both the green color of the sample and the absence of diffraction peaks [20,44,45,[54][55][56][57]. This result is supported by the Cu-X-ray mapping (figure 4 B) which shows a homogeneous distribution of copper on the support at the micrometric scale.…”

Microwave preparation of Ti-containing mesoporous materials. Application as catalysts for transesterification

“…Owing to a narrow and uniform pore size distribution, Ti-MCM-41-M393 has a smaller average pore size (28.6Å) and a higher surface area (896 m 2 /g) than any other Ti-MCM-41-M samples listed in Table 1. [30,31]. The band at 450 cm −1 is attributed to tetrahedral bending vibration of Si-O-Si bonds.…”