Sintering and coking resistant core–shell microporous silica–nickel nanoparticles for CO methanation: Towards advanced catalysts production

Modern engineered materials have to be developed to address specific problems associated to chemical processes that directly affect our society. Catalysts are key materials used for large scale production of at least 90% of the everyday goods. Many energy transformation chains exist in which catalysts are used at relatively high temperature. Therefore, deactivation due to sintering and poisoning is a common phenomenon and often the reason for unsuccessful implementation of new catalytic processes. In this paper, a Ni-based catalyst for CO methanation is studied with the aim to address two specific issues, namely the sintering and the carbon deposition, which both hinder the stability and the efficiency of the catalyst over time. The engineered material is composed by a Ni core of about 170 nm protected by a 30-40 nm microporous SiO2 layer. The porous layer allows the gases to permeate and completely inhibits particle-particle sintering. The experimental evidences demonstrate that even in the presence of 2000 ppm of C2H4 no carbon deposition occurs on the catalyst surface. The reported materials show outstanding properties paving the way to a new class of advanced functional material with improved catalytic activity and stability. (C) 2015 Elsevier B.V. All rights reserved

Electrochemical promotion of propane combustion on highly dispersed Pt nanoparticles

AIR+LLI:MTS:PVEPt nanoparticles, in a size range which varies from 3 to 20 nm, were dispersed in the porosity of a 7.5 mu m-thick layer of LSCF-GDC electrode interfaced on a dense GDC membrane. Small positive polarizations (200 mu A / 0.8V - 1.2V) can strongly increase the Pt nanoparticles catalytic performance for propane deep oxidation at low temperatures (267 degrees C-338 degrees C). 40%-enhancement of the propane conversion was achieved with apparent Faraday efficiency values up to 85. These results clearly demonstrate that metallic nanoparticles dispersed in the porosity of a mixed ionic electronic conducting electrode can be electropromoted

Electrochemical promotion of catalysis with highly dispersed Pt nanoparticles

Pt nanoparticles were dispersed in the porosity of a LSCF-GDC electrode interfaced on a dense GDC membrane. Small positive polarizations can strongly increase (38%-enhancement) the catalytic performance of Pt nanoparticles for propane deep oxidation at low temperatures with apparent Faradaic efficiency values up to 85. This study clearly demonstrates that the catalytic activity of metallic nanoparticles dispersed in the porosity of a mixed ionic electronic conducting electrode can be strongly electropromoted. Keywords: Electrochemical promotion, NEMCA effect, Pt nanoparticles, LSCF/GDC electrode, Post impregnatio

Ruthenium on phosphorous-modified alumina as an effective and stable catalyst for catalytic transfer hydrogenation of furfural

Supported ruthenium was used in the liquid phase catalytic transfer hydrogenation of furfural. To improve the stability of Ru against leaching, phosphorous was introduced on a Ru/Al2O3 based catalyst upon impregnation with ammonium hypophosphite followed by either reduction or calcination to study the effect of phosphorous on the physico-chemical properties of the active phase. Characterization using X-ray diffraction, solid state 31P nuclear magnetic resonance spectroscopy, X-ray absorption spectroscopy, temperature programmed reduction with H2, infrared spectroscopy of pyridine adsorption from the liquid phase and transmission electron microscopy indicated that phosphorous induces a high dispersion of Ru, promotes Ru reducibility and is responsible for the formation of acid species of Br\uf8nsted character. As a result, the phosphorous-based catalyst obtained after reduction was more active for catalytic transfer hydrogenation of furfural and more stable against Ru leaching under these conditions than a benchmark Ru catalyst supported on activated carb

Methanol dehydration to dimethylether over Al2O3-based catalysts

Μη διαθέσιμη περίληψηNot available summarizationΠαρουσιάστηκε στο: 11ο Πανελλήνιο Συμπόσιο Κατάλυση

NOx abatement in the exhaust of lean-burn natural gas engines over Ag-supported gamma-Al2O3 catalysts

SSCI-VIDE+CARE+YAZ:ABO:AGF:LRE:PVEInternational audienc

Mitigation of Secondary Organic Aerosol Formation from Log Wood Burning Emissions by Catalytic Removal of Aromatic Hydrocarbons

Log wood burning is a significant source of volatile organic compounds including aromatic hydrocarbons (ArHC). ArHC are harmful, are reactive in the ambient atmosphere, and are important secondary organic aerosol (SOA) precursors. Consequently, SOA represents a major fraction of the sub-micron organic aerosol pollution from log wood burning. ArHC reduction is thus critical in the mitigation of adverse health and environmental effects of log wood burning. In this study, two Pt-based catalytic converters were prepared and tested for the mitigation of real-world log wood burning emissions, including ArHC and SOA formation, as well as toxic carbon monoxide and methane, a greenhouse gas. Substantial removal of mono- and polycyclic ArHC and phenolic compounds was achieved with both catalysts operated at realistic chimney temperatures (50% conversion was achieved at 200 and 300 degrees C for non-methane hydrocarbons in our experiments for Pt/Al2O3 and Pt/CeO2-Al2O3, respectively). The catalytically cleaned emissions exhibited a substantially reduced SOA formation already at temperatures as low as 185-310 degrees C. This reduces the sub-micron PM burden of log wood burning significantly. Thus, catalytic converters can effectively reduce primary and secondary log wood burning pollutants and, thereby, their adverse health impacts and environmental effects