Preparation, Characterization and Catalytic Activity of Palladium Nanoparticles Embedded in the Mesoporous Silica Matrices

Abstract

Novel <i>in-situ</i> reduction approach was applied for the synthesis of palladium nanoparticles in the pores of mesoporous silica materials with grafted siliconhydride groups. Matrices possessing different structural properties (MCM-41, SBA-15 and Silochrom) were used. Samples were studied by nitrogen adsorption-desorption method, low-angle X-ray diffraction, transmission electron microscopy (TEM) and FT-IR/PAS spectroscopy. The temperature-programmed oxidation (TPO) and reduction (TPR) methods were applied to examine reducibility of palladium species. Palladium containing catalysts were tested in methane oxidation reaction. It was demonstrated that relatively large pores in SBA-15 type silica facilitated formation of well-dispersed palladium nanoparticles confined in the pores channels. In the case of MCM-41 support, metallic palladium nanoparticles were formed on the external surface. The obtained materials showed high catalytic activity. Lower activity of the samples containing small crystallites located in the pore volume at high temperatures was related to worse accessibility of active sites to the reation mixture

Oxidative Desulfurization of Hydrotreated Gas Oil using Fe2O3 and Pd Loaded over Activated Carbon as Catalysts

“…Also, there is a characteristic values for 2θ at 24.25° and 25.13° attributed to carbon particles which supported Fe 2 O 3 and Pd respectively. These results match with the earlier studies with simple variation due to the difference in the calcination temperature 19,21 .…”

Influence of annealing temperature on structural and magnetic properties of MnFe2O4 nanoparticles

“…This material can be used as a chemically, physically or biologically active-particle carrier. The nanosized particles have huge specifi c surface area and can be used as highly active catalysts [2,3]. Sometimes, the physical properties of nanomaterials are essentially different from those of the bulk counterparts and often exhibit new and surprising phenomena.…”

Surface-Functionalized Mesoporous Nanoparticles as Heterogeneous Supports To Transfer Bifunctional Catalysts into Organic Solvents for Tandem Catalysis

“…The peaks at around 1.5° and 2.4° in the small-angle XRD pattern could be assigned to the typical plane of MSN, thus confirming the successful preparation of mesoporous MSN (Figure S5). For the Pd-containing samples, the peaks centered at 2θ = 39.4°, 46.1°, 68.3°, and 81.1° in the wide-angle XRD pattern belong to the 111, 200, 220, and 311 diffraction maxima of metallic Pd characterized by its face-centered cubic structure, respectively. , The disappearance of the characteristic diffraction peaks at 1.5° and 2.4° in small-angle XRD is related to the destruction of the regular mesoporous structure of MSN caused by the incorporation of Pd, which indicates the filling of the MSN pore channels by Pd NPs. , The specific surface areas and porosities of the resultant materials were measured by the N 2 adsorption/desorption experiments. The curve of MSN represents a type-IV isotherm pattern, indicating mesoporosity .…”