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A simple method to prepare magnesium oxide catalysts for biodiesel production by transesterification reaction of soybean oil with ethanol is proposed. The method was developed using a metal-chitosan complex. Compared to the commercial oxide, the proposed catalysts displayed higher surface area and basicity values, leading to higher yield in terms of fatty acid ethyl esters (biodiesel). The deactivation of the catalyst due to contact with CO 2 and H 2 O present in the ambient air was verified. It was confirmed that the active catalytic site is a hydrogenocarbonate adsorption site.

Here we describe a new route for the synthesis of nanometric Ni particles embedded in a mesoporous silica material with excellent potential for catalytic applications. Mesoporous silica with a surface area in the range of 202-280 m2/g, with narrow pore size distribution and Ni nanoparticles (particles in the range of 3-41 nm) were obtained in a direct process. A different approach was adopted to process such a nanocomposite. This new approach is based on the formation of a polymer with the silicon oxianion and nickel cation chelated to the macromolecule structure and on the control of the pyrolysis step. The CO/CO2 atmosphere resulting from the pyrolysis of the organic material promotes the reduction of the Ni citrate.

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Abstract:We describe the synthesis of AgPt hollow nanodendrites employing Ag nanospheresass eeds by combining agalvanic replacement reactionbetween Ag and PtCl 6 2À and PtCl 6 2À reduction to Pt in the presence of hydroquinone. AgPt hollow nanodendrites comprised of severalP ti slands % 6nmi nd iameter could be obtained in only 15 sf ollowing the addition of PtCl 6 2À to as uspension containing Ag nanospheres, andt heir size and composition could be tuned as af unction of the growth time. Thes ynthesis could be scaled up by 100 folds, which enabled us to uniformly support the AgPt nanostructures onto commercial silica. The AgPt nanodendrites displayed good catalytic activities for both the 4-nitrophenol reduction and the BTX oxidation reactions. The results presented herein mayi nspire the synthesis of noble metal nanostructures displaying attractive features for catalysis, such as hollow interiors, ultrathin walls, and uniform dispersion over solid supports (solid supported catalysts).

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