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Metal–organic framework (MOF) supported nanocatalysts are attracting great attentions in heterogeneous catalysis. However, they are still less explored and poorly understood in catalyzing solid–gas reactions. In current work, two MOF supported Pt nanocatalysts were prepared by immersion method coupled with the most commonly used NaBH4 (Pt/UiO-66-NaBH4) and H2 (Pt/UiO-66-H2) reduction, and their catalytic CO oxidation performances were investigated. NaBH4 and H2 reduction both provide highly dispersed Pt/UiO-66 nanocatalysts, and the two prepared catalysts display excellent CO oxidation activities. Moreover, CO oxidation durability tests reveal that Pt/UiO-66-NaBH4 shows superior durability and structure stability, which are much better than those of Pt/UiO-66-H2. The high structure stability of Pt/UiO-66-NaBH4 also endows it with good H2O and CO2 tolerance. This work attempts to elucidate the influence of reduction methods on the structures and catalytic CO oxidation performances of Pt/UiO-66 catalysts by employing XRD, TEM, N2-sorption, XPS and in situ DRIFTS techniques. Furthermore, the mechanism of CO oxidation was studied by in situ DRIFTS, and the result reveals that the CO oxidation on the two catalysts follows different mechanism. [ABSTRACT FROM AUTHOR]

Abstract: Dimethyldichlorosilane is the most versatile of organosilicon monomers and is produced in large quantites. In this paper, MP2/6-311++G (3df, 2pd) basis set has been used to calculate the reaction mechanism of disproportionation for producing dimethyldichlorosilane by catalyst AlCl3/(AlCl2)-γ-Al2O3 (Z = 0-2). The activation energy (Z = 0-2) of the rate-determining step of main reaction is: 73.00, 60.26, and 66.39 kJ mol-1. By comparing the activation energy and reaction heat, it is found that the catalytic effect of AlCl3/(AlCl2)-γ-Al2O3 (Z = 1) is the best. [ABSTRACT FROM AUTHOR]

Density functional theory calculations have been carried out to explore the reaction mechanisms for the reactions of “frustrated Lewis pairs” (FLPs) with small molecules. Four reactions were studied in the present investigation. A new N-heterocyclic carbene borane, boron amidinate compound HC(iPrN) 2B(C 6F 5) 2 ( 1), classified as FLPs, was chosen as the common reactant of these reactions. It was used to react with CO 2, CO, and two terminal alkynes, methylacetylene and phenylacetylene. The reactions of 1 with CO 2 and CO can both be regarded as the concerted addition mechanisms. In these reactions, the formations of the C2–N2 and B–O1 bonds take place simultaneously. For the reactions of 1 and methylacetylene or phenylacetylene, our calculations indicated that a deprotonation pathway and the connection between B atoms and terminal alkyne C atoms occur by a concerted manner simultaneously, together with the connection between N2 and hydrogen atoms. We also investigated the reaction mechanisms according to the frontier molecular orbital (FMO) theory and carried out electric charge analyses, finding that the two results were consistent with each other perfectly. Electric charges transfer from HOMO of 1_OPEN to LUMO of CO 2 or CO. In contrast, electric charges transfer from HOMO of methylacetylene or phenylacetylene to LUMO of 1_OPEN. [ABSTRACT FROM AUTHOR]

TiO nanoparticles have been synthesized on the surface of exfoliated montmorillonite at a low temperature in benzyl alcohol medium. According to X-ray diffraction (XRD), N adsorption-desorption isotherm and transmisson electron microscopy (TEM), it was found that the intercalation of TiO nanoparticles destroyed the ordered structure of montmorillonite to some extent, and the crystallites of the nanocomposites are assembled to form a house-of-cards structure. The size of the nanoparticles in the interlamellar space is about 4 nm. The nanocomposites exhibited excellent photocatalytic activity in methylene blue degradation due to the synergetic effect of the adsorptive ability to organic compound of cetyl trimethylammonium bromide—montmorillonite and the catalytic ability of TiO nanoparticles in it. [ABSTRACT FROM AUTHOR]

Abstract: Organosilicon material is widely used because of its dual structure. Dimethyldichlorosilane is the largest and most versatile of organic silicon monomer. In this article, MP2/6-311 ++G (3df, 2pd) basis set has been used to calculate the reaction mechanism of disproportionation for producing dimethyldichlorosilane by catalysts AlCl3/ZSM-5 (3T, 4T, 6T). The results show that the activation energies (3T, 4T, 6T) of the rate-determining step of the main reaction are: 100.3, 110.6 and 113.1kJmol-1, respectively. The structure analysis, activation energy analysis and LOL analysis for different catalysts all show that the catalytic effect of 4T cluster AlCl3/ZSM-5 is the best.Graphical Abstract: SYNOPSIS The disproportionation of methyltrichlorosilane and trimethylchlorosilane, catalyzed by 3T cluster AlCl3/ZSM-5 (Cat.4T and Cat.6T are same as Cat.3T). It has been studied theoretically. The results suggest that the catalytic effect of 4T cluster AlCl3/ZSM-5 is the best. PICTOGRAM [ABSTRACT FROM AUTHOR]