heterogeneous ziegler-natta and homogeneous metallocene catalysts exhibit greatly different active sitenature in olefin polymerization. in our previous study, it was reported that mgcl2-supported titanocenecatalysts can generate both ziegler-natta-type and metallocene-type active sites according to the type of activators.the dual active site nature of the supported titanocene catalysts was furt...

several types of hybrid catalysts are made through mixing of 4th generation ziegler-natta (zn) and (2-phind)2zrcl2metallocene catalysts using triethylaluminum (tea) as coupling agent. response surface methodology (rsm)is used to evaluate the interactive effects of different parameters including amounts of metallocene and tea andtemperature on metallocene loading. analyzing the amounts of al and...

We report on the activity of fullerene-supported OsO(4) catalysts in the achiral dihydroxylation of olefins using N-methylmorpholine N-oxide as co-oxidant. The fullerene-supported OsO(4) catalysts can selectively dihydroxylate olefins with conversions up to 95% after 48 h without leaching, and the catalysts can be recovered and recycled several times.

Catalysts with the formula of LaCo(1+x)O(3+δ), where 0 ≤ x ≤ 1, were studied for oxidation of CO and C2H6 in a synthetic exhaust gas, comprising 6.0 % CO and 0.2 % C2H6 in Ar. Ethane was selected as a model for hydrocarbons in the exhaust gas. The performance of catalysts is correlated to their properties, particularly their ...

A critical step in creating an artificial photosynthesis system for energy storage is designing catalysts that can thrive in an assembled device. Single-site catalysts have an advantage over bimolecular catalysts because they remain effective when immobilized. Hybrid water oxidation catalysts described here, combining the features of single-site bis-phosphonate catalysts and fast bimolecular bi...

Supported gold nanoparticles are highly selective catalysts for a range of both liquid-phase and gas-phase hydrogenation reactions. However, little is known about their stability during gas-phase catalysis and the influence of the support thereon. We report on the activity, selectivity, and stability of 2-4 nm Au nanoparticulate catalysts, supported on either TiO2 or SiO2, for the hydrogenation...

This paper presents the synthesis and characterization of monometallic and bimetallic cobalt and iron nanoparticles supported on alumina. The catalysts were prepared by a wet impregnation method. Samples were characterized using temperature-programmed reduction (TPR), temperature-programmed oxidation (TPO), CO-chemisorption, transmission electron microscopy (TEM), field emission scanning electr...

This review is focused on the strategies and designs of magnetic nanostructured catalysts showing the enhanced and sustainable catalytic performances for the heterogeneous reduction of nitoaromatics. Magnetic catalysts have the benefits of easy recovery and reuse after the completion of the reactions and green chemical processes. Magnetic separation, among the various procedures for removing ca...

An extensive series of supported WO3/ZrOx (OH)4−2x catalysts (WZrOH) were synthesized by standard aqueous impregnation of ammonium metatungstate into an amorphous ZrOx (OH)4−2x metastable support, followed by high-temperature calcination (at 773–1173 K). The supported WZrOH catalysts were also compared with well-defined model supported WO3/ZrO2 catalysts (WZrO2) consisting of a thermally stable...

The encapsulation of homogeneous chiral catalysts, e.g. Co(Salen) and Ru-TsDPEN, in the mesoporous cage of SBA-16 is demonstrated; the encapsulated catalysts show performance as good as that of the homogeneous catalysts, and can be recycled for more than 10 times without significant loss of catalytic performance.