Synthetic Hydrotalcites as suitable Co-based catalysts for Fischer-Tropsch Process

Nowadays it is imperative to develop economical and energy-efficient processes for the sustainable production of alternative fuels and chemicals. Fischer Tropsch synthesis (FT) is a well-established industrial process whereby these objectives can be achieved using syngas (mixture of H2, CO, CO2) as raw material. Syngas can be manufactured from CH4, coal or, as a new tendency, frombiomass. FT synthesis usually requires catalysts based on cobalt or iron. The typical products range is from methane to long chain hydrocarbons (waxes) [1]. Cobalt-based catalysts have been used for FT for long time due to their long life-times, high CO conversion and high selectivity to heavy hydrocarbons; they are moreover characterized by low activity towards the water-gas shift, so avoiding the CO2 formation. In this work, layered double or triple hydroxides, also known as synthetic hydrotalcites, are proposed and studied as FT catalysts. The choice of these materials allows to easily prepare solid phases, essentially based on mixed metal oxides, where specific metal atoms are homogeneously dispersed at an atomic level. Hydrotalcites are represented by the empirical formula [M(II)1-xM(III)x(OH)2]x+[An-x/n]x-mH2O where M(II) is a divalent cation such as Co, Mg, Zn, Ni, or Cu, M(III) is a trivalent cation such as Al, Cr, Fe or Ga; An- is an anion of charge n and m the molar amounts of co-intercalated water [2]. When calcined at proper temperatures, the random distribution of cations, characteristic of the hydroxide phase, is maintained in the resulting mixed oxide. Hydrotalcite based materials have been recently reported as good catalysts for several processes in the energy field, such as hydrogen production by steam reforming of methanol and ethanol, photocatalytic water splitting and so on [3-5]. A series a Co-Zn-Al hydrotalcites, with increasing Co contents was synthesized and characterized. Preliminary tests on their catalytic activity in the FT process resulted in a satisfactory outcome

The “Historical Materials BAG”: A New Facilitated Access to Synchrotron X-ray Diffraction Analyses for Cultural Heritage Materials at the European Synchrotron Radiation Facility

The European Synchrotron Radiation Facility (ESRF) has recently commissioned the new Extremely Brilliant Source (EBS). The gain in brightness as well as the continuous development of beamline instruments boosts the beamline performances, in particular in terms of accelerated data acquisition. This has motivated the development of new access modes as an alternative to standard proposals for access to beamtime, in particular via the “block allocation group” (BAG) mode. Here, we present the recently implemented “historical materials BAG”: a community proposal giving to 10 European institutes the opportunity for guaranteed beamtime at two X-ray powder diffraction (XRPD) beamlines—ID13, for 2D high lateral resolution XRPD mapping, and ID22 for high angular resolution XRPD bulk analyses—with a particular focus on applications to cultural heritage. The capabilities offered by these instruments, the specific hardware and software developments to facilitate and speed-up data acquisition and data processing are detailed, and the first results from this new access are illustrated with recent applications to pigments, paintings, ceramics and wood

Role of the solvent in the US-assisted preparation of TiO2 for the photocatalytic degradation of sulfamethoxazole in water

This work presents a study concerning the role of the solvent in the US-assisted preparation of TiO2 for the photocatalytic degradation of sulfamethoxazole in water. Different solvente were tested in the catalyst preparation and the obtained results in a batch reactor discussed

Influence of π-π Stacking interactions on the assembly of layered copper phosphonate coordination polymers: Combined powder diffraction and electron paramagnetic resonance study

Three new copper phosphonate coordination polymers have been obtained following very soft synthetic routes, and their structures were determined ab initio from powder X-ray diffraction data. They are based on the two building blocks α,α′-m-xylylenediphosphonic and α,α′- p-xylylenediphosphonic acid, either exclusively or combined with 4,4′-bipyridine as an ancillary ligand. The compound obtained from α,α′-m-xylylenediphosphonate has the formula Cu(HO 3PCH 2) 2C 6H 4•3H 2O and a 2D structure of mixed organic-inorganic layers built up by the connection of inorganic chains made of edge-sharing copper octahedra via organic bridging groups. The compound obtained from α,α′-m- xylylenediphosphonate and 4,4′-bipyridine as a coligand has the formula Cu[(HO 3PCH 2) 2C 6H 4][N(CH) 4CC(CH) 4N]•2H 2O and a 2D structure based on the connection, via the diphosphonic ligand, of the linear chains resulting from the bridging of copper atoms by the bipyridine moieties. The compound obtained using α,α′-p-xylylenediphosphonate and 4,4′-bipyridine as a coligand has the same formula and a 2D structure closely resembling that of the previous compound. The influence of the factors driving the molecular assembly is discussed, pointing out the crucial role played by the 4,4′-bipyridine in promoting the π-π stacking interactions. With increasing temperatures, the compounds revealed a loss of water molecules bound to copper; in particular, heating the copper α,α′-m-xylylenediphosphonate-bipyridine results in a relatively stable phase with unsaturated coordination sites on the metal atoms. This behavior was confirmed by magnetic susceptibility and electron paramagnetic resonance measurements which also provided evidence for a partial reversibility of the dehydration process and of the occurrence of weak antiferromagnetic interactions between Cu(II) ions. © 2012 American Chemical Society

Immunolocalization of the receptors for urokinase plasminogen activator (uPAR) in bladder carcinoma

The work reports the immunolocalization of the receptors for urokinase plasminogen activator (uPAR) in bladder carcinom

Espressione del recettore per l\u2019urokinase plasminogen activator (uPAR) nel carcinoma della vescica: studio al microscopio elettronico

Il lavoro riporta l'analisi immunocitochimica ultrastrutturale dell'epressione del recettore per l\u2019urokinase plasminogen activator (uPAR) nel carcinoma della vescic