Inorganic oxide support

One advantage of sol-gel processing over surface modification is to create the inorganic oxide support in situ. Hence, without the limitation of the surface area of particles, more organic groups can be incorporated, even though their accessibility is not warranted. Another advantage is the possibility to... 

In recent years, modification of zeolites, such as HZSM-5, by phosphoric compounds or metal oxides has been extensively studied, but little information is available on the modification of zeolites by diazomethane, which is an excellent methylating agent for protonic acidic sites. It is capable of entering into the small pores of zeolites because of its small molecular size and linear molecular structure. Yin and Peng (1,2) reported that the acidity and specific surface area of the inorganic oxide supports (AljOs, SiOj) and zeolite catalysts... 

Sn(PC)] and [Sn(PC)Cl2] were prepared by the method of Kroenke and Kenney. (20) Hexadecane (certified) and quinoline were distilled prior to use. Inorganic oxide supports were from commercial sources and have the following properties AI2O3,... 

Prior to the reaction, the inorganic oxide support is thermally pretreated to remove physisorbed water and thus avoid spurious reactions which would not lead to anchoring/grafting. The support can be also dchy-droxylated to various extents to control the amount and dispersion of the anchored/graftcd species. Different types of hydroxy groups with different reactivities are present on supports. The structure of support surfaces and their reactivity have been extensively described in several reviews ([12-18] and references therein). 

Bando KK, Asakura K, Arakawa H, Isobe K, Iwasawa Y (1996) Surface structures and catalytic hydroformylation activities of rh dimers attached on various inorganic oxide supports. J Phys Chem 100 13636... 

Sinfelt has greatly contributed to the catalyses of bimetallic nanoparticles [18]. His group has thoroughly studied inorganic oxide-supported bimetallic nanoparticles for catalyses and analyzed their microstructures by an EXAFS technique [19-22]. Nuzzo and co-workers have also studied the structural characterization of carbon-supported Pt/Ru bimetallic nanoparticles by using physical techniques, such as EXAFS, XANES, STEM, and EDX [23-25]. These supported bimetallic nanoparticles have already been used as effective catalysts for the hydrogenation of olefins and carbon-skeleton rearrangement of hydrocarbons. The alloy structure can be carefully examined to understand their catalytic properties. Catalysis of supported nanoparticles has been studied for many years and is practically important but is not considered further here. 

The extension of our previous work on yttria-doped alumina to three other inorganic oxide supports currently employed in catalysis resulted in similar advantages. The next step will be to deposit a precious metal on the doped oxides and to compare the results obtained in a reaction test with the non-doped supported catalysts. 

The electron microscopes can be divided into two types (166) scanning electron microscopes (SEM), which use a 10-nm electron beam at the specimen surface, and transmission electron microscopes (TEM). With current TEMs, resolution of about 0.2 nm can be achieved, provided very thin (<20 nm) samples are available. With conventional inorganic oxide-supported metal catalysts, particles of approximately 1 nm can be detected. Scanning transmission electron microscopes (STEM) use a high brightness dark-field emission gun to produce a probe about 0.3 nm in diameter and combine the techniques of SEM and TEM. Further experimental and theoretical aspects of electron microscopy applied to catalysis have been reviewed recently (113, 167-169). 

The Ni a-diimine catalysts may be supported on a wide range of inorganic oxide supports,but silica... 

Figure 18 shows a high resolution, transmission electron microscopy image of the mesoporous inorganic oxide support with embedded Zeolite Beta, and an inset showing an electron diffraction ( ED ) pattern of the zeolite domain (27). The ED pattern clearly shows that the Zeolite Beta has retained its crystallinity. 

Attachment to the Support via Adsorption onto Inorganic Oxide Supports In 2008, Sels, Jacobs, and coworkers [89] described a simple process, where catalyst 5 was adhered onto silica, and the resulting material was employed in batch and continuous-flow metathesis applications. When both the substrates and reaction media were nonpolar, the system worked effectively however, when polar substrates were introduced, Ru was leached from the material. This observation was further supported when the catalytic system passed a cyclooctene, ROMP-based split-test performed in hexane, yet failed the same experiment in diethyl ether. Likewise, the adhered catalyst performed well in continuous-flow processing of cyclooctene in hexane however, no continuous-flow results were reported using polar substrates. 

Two popular methods of graft polymerization onto inorganic oxide supports (silica, alumina, and zirconia) are free-radical polymerization [16-34] and anioni-cally initiated polymerization [12, 35-37]. Studies have demonstrated that free-radical graft polymerization onto surface-active vinyl alkoxysilanes is an efficient and controllable method for obtaining a high polymer graft yield in the dense brush ... 

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