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Synergistic redox active sites of Cu–Ce-based catalysts are susceptible to CO2 occupation during CO preferential oxidation (CO-PROX). Herein, an exquisite nanotube/rod-shaped CuO/CeO2 catalyst is prepared by in situ growing ceria nanotubes from Ce-(OH)-CO3 and uniformly impregnating copper, leading to remarkable catalytic activity and CO2 resistance for CO-PROX. The distinctive crystal planes imparted by the special nanotube/rod-shaped morphology facilitate the dispersion of Cu species and enhance the interaction at the active Cu–O–Ce interface, resulting in an abundance of metal valence states and oxygen vacancies, as opposed to rod-shaped and irregularly shaped CuO/CeO2 catalysts. More crucially, in situ diffuse reflectance infrared Fourier transform spectroscopy (in situ DRIFTS) and carbon dioxide temperature-programmed desorption (CO2-TPD) analyses reveal that the surface-regenerated tubular structure of the catalyst expedites CO2 desorption. Additionally, the expansion of the hollow structure ameliorates the activity and stability of the catalysts by promoting metal dispersion and CO2 desorption. [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]

Geometric and electronic properties and vacancy formation energies for two kinds of oxygen-vacancy Cu2O (111) surfaces have been investigated by first-principles calculations. Results show that the relaxation happens mainly on the top three trilayers of surfaces. Two vacancies trap electrons of -0.11e and -0.27e, respectively. The effects of oxygen vacancies on the electronic structures are found rather localized. The electronic structures suggest that the oxygen vacancies enhance the electron donating ability of the surfaces to some extent. The energies of 1.75 and 1.43 eV for the formation of oxygen vacancies are rather low, which indicates the partially reduced surfaces are stable and easy to produce. [ABSTRACT FROM AUTHOR]

The adsorption of CO2, and its derivatives, H2CO3, HCO [ABSTRACT FROM AUTHOR]

In view of the wide application of organosilicon bifunctional structure in industry, the most effective disproportionation solution is used by the new catalyst to prepare the largest and the most versatile organic silicon monomer dimethyldichlorosilane. However, there are still remaining doubts on the disproportionation mechanism of the catalyst. The Density Functional Theory (DFT) was used to theoretically calculate the disproportionation mechanism of 5 T clusters ZSM‐5@γ‐Al2O3 series catalysts at the B3LYP/6–311++G(3df, 2pd) level. The properties were verified and the catalytic effects of different active sites pre‐ and post‐ modified by AlCl3 were calculated and compared. The active center of HZSM‐5@γ‐Al2O3 was proton, and that of AlCl3/ZSM‐5@γ‐Al2O3 changed to lewis acidic center. The presence of the lewis acid center enhances the total activity of the catalyst to some extent. The catalytic activity of the 5 T cluster ZSM‐5@γ‐Al2O3 catalyst modified by AlCl3 was higher, which was the same as the experimental results. [ABSTRACT FROM AUTHOR]

Highlights: [•] CO2 adsorption on Cu2O (111) oxygen-vacancy surface was investigated theoretically. [•] Oxygen vacancies are the active sites. [•] radical anion species can be formed only at the oxygen-vacancy sites. [•] Vacancies negatively affect CO2 adsorption at the CuCUS and OCUS sites. [Copyright &y& Elsevier]