Copper supported on mixed alumina/gallium oxide pillared a-tin phosphate for De-NO x applications

Alumina-and mixed alumina/gallium oxide-pillared a-tin phosphate have been impregnated with different amounts of copper via the incipient wetness method. Their characterization by X-ray photoelectron spectroscopy, H 2 temperature-programmed reduction and NO temperature-programmed desorption has allowed to gain insight into the nature of the copper species. These are present as small CuO clusters (not detectable by XRD) as well as forming part of spinel-like structures. NO-TPD studies show that only NO is desorbed from all the catalysts. Ga 3 Al 11 -SnP with 4.9 wt% Cu interacts most strongly with NO and this catalyst exhibits the highest degree of reduction of Cu 2+ to Cu + after the catalytic reaction. The catalysts are active for the selective catalytic reduction (SCR) of nitric oxide with propane in the presence of excess oxygen

Application of zeolites for the production of biofuels and furans from hexose sugars in ethanol.

The use of zeolites as catalysts in the transformation of glucose and 5-hydroxymethylfurfural (HMF) into 5-ethoxymethylfurfural (EMF) was evaluated. The behaviour of the catalysts could be explained by their morphology, composition, acid properties and chemical coordination of the active sites. The progress of the reaction was followed by High Performance Liquid Chromatography (HPLC) and 13C Nuclear Magnetic Resonance (NMR). Several intermediates were identified, and a reaction path is proposed. Different cosolvents were also employed in this study to enhance the selectivity towards different possible valuable compounds, and they were found to have a positive influence for the production of EMF and furfural.Funding for open access charge: Universidad de Málaga / CBU

Preparation, characterization and catalytic applications of ZrO2 supported on low cost SBA-15

This work presents some applications of ZrO2 supported over SBA-15 silica as promoter of sulfated zirconia and as support from CuO/CeO 2 catalytic system for preferential oxidation of CO to CO2 in hydrogen rich streams, used as feed for proton exchange membrane fuel cells (PEMFC). Different amounts of ZrO2, from 10 to 30 wt.% were incorporated. These prepared materials were characterized by powder XRD, adsorption-desorption of N2 at 77 K, transmission and scanning electron microscopy (TEM and SEM) and X-rays photoelectron spectroscopy (XPS). The acidity was studied by thermo-programmed desorption of ammonia (NH 3-TPD). These materials were tested, after treatment with H 2SO4, by 2-propanol dehydration and 1-butene isomerization catalytic tests. The samples were found quite good catalyst with strong acid sites, the sample with 20 wt.% of ZrO2 being the better performing sample. Finally this material was successfully used as support for a CuO/CeO2 system, with 6 wt.% of Cu and 20 wt.% of Ce. The resulting catalyst was tested in the preferential oxidation of CO (CO-PROX) attaining conversions close to 100% and high selectivity to CO2

Sur l’orientation de molécules basiques dans l’espace interlamellaire du phosphate d’étain

On a étudié l’intercalation de molécules basiques nitrogénées de différentes structures moléculaires, telles que les alkylamines, α, ω-alkyldiamines, hétérocycles aromatiques, et de l’ion cétylpyridinium dans le phosphate d’étain. A partir des données de la diffraction de rayons X et de la composition chimique on a établi une corrélation entre la nature de l’espèce intercalée et son orientation dans la région interlamellaire

Dehydration of xylose to furfural using a Lewis or Brönsted acid catalyst and N2 stripping

The activity of Lewis (Nb2O5) and Brönsted (Amberlyst 70) acid catalysts for the cyclodehydration of xylose to furfural was studied. The nature of the acidity resulted in significant changes in the reaction mechanism. Lewis acid sites promote the formation of xylulose, while Brönsted acid sites are required to further dehydrate the sugar to furfural. Amberlyst 70 in water/toluene at 175 °C showed lower activity but gave a higher furfural yield. Using N2 as the stripping agent considerably improved the furfural yield and product purity in the stripped stream. Catalyst stability was also studied.This work was supported by funds from the Spanish Ministerio de Economía y Competitividad (CTQ-2012-38204-C03-03 and ENE2009-12743-C04-03) and from the Gobierno Vasco (Programa de Formación de Personal Investigador del Departamento de Educación, Universidades e Investigación). The authors are also grateful to the Junta de Andalucía (P09-FQM-5070) for financial support.Peer Reviewe

The role of nitride species in the gas-phase furfural hydrogenation activity of supported nickel catalysts

A series of C-rich nickel nitride nanoparticles supported on silica has been prepared by the urea glass route, with urea as nitrogen and carbon source, and characterized by different physico-chemical techniques. They consist of Ni3N nanoparticles of 20−25 nm embedded into a carbonaceous matrix. These catalysts are much more active and stable than a nickel supported silica catalyst, which drastically deactivates. The supported Ni3N catalyst with a 10 wt.% Ni maintained a furfural conversion higher than 80 % after 5 h of time-on-stream, at 170 °C, with a high WHSV of 6 h−1. Complete initial furfural conversion values were observed at reaction temperatures varying from 170 to 230 °C, and the selectivity toward furan and furfuryl alcohol (decarbonylation and hydrogenation products, respectively) was tuned by varying this temperature. After the catalytic tests, XPS and XRD have demonstrated that nanoparticles are stable, although carbonaceous deposits were also detected