In-situ Raman spectroscopy study of Ru/TiO2 catalyst in the selective methanation of CO

Raman spectroscopic technique has been used to characterize a Ru/TiO2 catalyst and to follow in situ their structural changes during the CO selective methanation reaction (S-MET). For a better comprehension of the catalytic mechanism, the in-situ Raman study of the catalysts activation (reduction) process, the isolated CO and CO2 methanation reactions and the effect of the composition of the reactive stream (H2O and CO2 presence) have been carried out. Raman spectroscopy evidences that the catalyst is composed by islands of TiO2¿RuO2 solid solutions, constituting Ru¿TiO2 interphases in the form of RuxTi1 xO2 rutile type solid solutions. The activation procedure with H2 at 300 °C promotes the reduction of the RuO2¿TiO2 islands generating Ruo ¿Ti3+ centers. The spectroscopic changes are in agreement with the strong increase in chemical reactivity as increasing the carbonaceous intermediates observed. The selective methanation of CO proceeds after their adsorption on these Ruo ¿Ti3+ active centers and subsequent C-O dissociation throughout the formation of CHx/CnHx/CnHxO/CHx-CO species. These intermediates are transformed into CH4 by a combination of hydrogenation reactions. The formation of carbonaceous species during the methanation of CO and CO2 suggests that the CO presence is required to promote the CO2 methanation. Similar carbonaceous species are detected when the selective CO methanation is carried out with water in the stream. However, the activation of the catalysts occurs at much lower temperatures, and the carbon oxidation is favored by the oxidative effect of water.España Mineco ENE2012- 37431-C03-03Unión Europea Junta de Andalucia FEDER TEP-819

Artificial Adaptive Systems and predictive medicine: a revolutionary paradigm shift

An individual patient is not the average representative of the population. Rather he or she is a person with unique characteristics. An intervention may be effective for a population but not necessarily for the individual patient. The recommendation of a guideline may not be right for a particular patient because it is not what he or she wants, and implementing the recommendation will not necessarily mean a favourable outcome

The second sphere coordination of peroxovanadium guests with polyurea, polyguanidinium and polyammonium hosts /

New insulin mimetic peroxovanadium compounds were prepared as polyguanidinium, ammonium and polyammonium salts, and their cation-anion interactions were characterized by UV-Vis, 51V NMR and 1H NMR spectroscopy. The X-ray structures of four complexes [((NH2) 3 CCH2CH2)2][mpV(nta)], [(NH2NH) 2C(NH2)][mpV(2,6-pdc)], [((NH2)2 C(NH) (CH2)3)2(N2C4H 8)][bpV(pic)]·2H2O, and [(NH3 CH2 CH2)2][bpV(bipy]·H2O, were determined and are discussed.[Et4N][bpV(phen)]·2H2O was prepared and its ability to act as a guest to second sphere coordinating polyurea hosts, in chlorofoml/DMSO, was studied using NOESY, 51V NMR and 1H NMR; extraction, titration and VT experiments.The relative stability of 6 complexes in DMEM media, assessed using 51V NMR, is discussed with respect to decomposition products and toxicities in PC-12 cells. Decomposition rates depend upon the number of peroxo groups (1 > 2) and the ancillary ligands

Catalytic methanation reaction over supported nickel-ruthenium oxide base for purification of simulated natural gas

The presence of carbon dioxide and water molecules as impurities in crude natural gas decreases the quality of natural gas. Recently, the catalytic treatment of this toxic and acidic gas has become a promising technique by converting CO2 to methane gas in the presence of H2S gas; thus, enhancing methane production and creating an environmentally friendly approach to the purification of natural gas. A series of catalysts based on nickel oxide were prepared using the wetness impregnation technique and aging, followed by calcination at 400 °C. Pd/Ru/Ni(2:8:90)/ Al2O3 catalyst was revealed as the most potential catalyst, and achieved 43.60% of CO2 conversion, with 6.82% of methane formation at 200 °C. This catalyst had the highest percentage of 52.95% CO2 conversion and yielded 39.73% methane at a maximum temperature of 400 °C. In the presence of H2S in the gas stream, the conversion dropped to 35.03%, with 3.64% yield of methane at a reaction temperature of 400 °C. However, this catalyst achieved 100% H2S desulfurization at 140 °C and remained constant until the reaction temperature of 300 °C. Moreover, the XRD diffractogram showed that the catalyst is highly amorphous in structure, with a BET surface area in the range of 220–270 m2 g- 1. FESEM analysis indicated a rough surface morphology and non-homogeneous spherical shape, with the smallest particles size in the range 40–115 nm