SiO 2 and ZrO 2 supported Ni catalysts were prepared for the steam reforming of ethanol. The catalytic performances, in terms of both H 2 productivity and stability towards coking and sintering, were related to the physico-chemical properties of the catalysts. The samples were prepared either by synthesis of the support by precipitation and subsequent impregnation with the active phase, or by direct synthesis through flame pyrolysis (FP). The latter has been chosen because it leads to nanostructured oxides, characterised by high thermal resistance, important for this high temperature application.The samples showed different textural, structural and morphological properties, as well as different reducibility and thermal resistance, depending on the preparation method and support.One of the key parameters governing the final catalyst properties was metal-support interaction. In particular, the stronger the latter parameter, the higher was metal dispersion, leading to small and stable Ni clusters. This influenced both activity and the resistance towards coking.Surface acidity was also taken into account considering the effect of the different nature of acid sites (silanols or Lewis a.s.) of both support and metal phase on catalyst deactivation.The best results were obtained with a 10 wt% Ni/SiO 2 sample, prepared by FP, when tested at 625°C. H 2 productivity of 1.44 mol H 2 /min kg cat was reached, corresponding to ca. 80% of the maximum value achievable under the selected conditions. This result was accompanied by the lowest CO/CO 2 ratio, which simplifies H 2 purification steps for use in fuel cells, and 100% carbon balance without by-products in the outflowing gas.

ABO3 perovskite-like catalysts are known to be sensitive to sulphur-containing compounds. Possible solutions to increase resistance to sulphur are represented by either catalyst bed protection with basic guards or catalyst doping with different transition or noble metals. In the present work La(1-x)A'xCoO3, La(1-x)A'xMnO3 and La(1-x)A'xFeO3, with A' = Ce, Sr and x=0, 0.1, 0.2, either pure or doped with noble metals (0.5 wt% Pt or Pd), were prepared in nano-powder form by flame pyrolysis. All the catalysts were tested for the catalytic flameless combustion of methane, monitoring the activity by on-line mass spectrometry. The catalysts were then progressively deactivated in operando with a new procedure, consisting of repeated injection of some doses of tetrahydrothiophene (THT), usually employed as odorant in the natural gas grid, with continuous analysis of the transient response of the catalyst. The activity tests were then repeated on the poisoned catalyst. Different regenerative treatments were also tried, either in oxidising or reducing atmosphere.Among the unsubstituted samples, higher activity and better resistance to poisoning have been observed in general with manganites with respect to the corresponding formulations containing Co or Fe at the B-site. The worst catalyst showed LaFeO3, from both the points of view of activity and of resistance to sulphur * Corresponding author: fax +39-02-50314300, e-mail ilenia.rossetti@unimi.it 2 poisoning. La0,9Sr0,1MnO3 showed, the best results, exhibiting very high activity and good resistance even after the addition of up to 8.4 mg of THT per g of catalyst.Interesting results were attained also by adding Sr to Co-based perovskites. Sr showed a first action by forcing Mn or Co in their highest oxidation state, but, in addition, it could also act as a sulphur guard, likely forming stable sulphates due to its basicity. Among noble metals, Pt doping proved beneficial in improving the activity of both the fresh and the poisoned catalyst.Keywords: Methane, catalytic combustion; Sulphur poisoning; Perovskite-like catalysts. -INTRODUCTIONThe catalytic flameless combustion (CFC) of methane outperforms conventional flame combustion because of lower emission of pollutants (HC, CO and NOx) and high thermal efficiency. The catalysts traditionally used for CFC are mainly based on supported noble metals, such as Pd and Pt, which ensure high activity, however accompanied by some drawbacks, due to high cost and poor thermal and chemical stability. La-based catalysts with ABO3 perovskite-like structure [1][2][3][4] have been proposed as a valid alternative for the present application. Indeed, perovskite catalysts combine low cost, thermo-chemical stability at high operating temperature and satisfactory catalytic activity [5][6][7][8]. In spite of this, there are still some open questions, especially regarding their resistance to sulphur poisoning when used for the CFC of methane. Indeed, the poisoning mechanism of perovskite-like catalysts has not been completely understood a...

Ag represents an interesting dopant for the highly active LaCoO3 perovskites used for the catalytic flameless combustion (CFC) of methane, due to its ability to adsorb and activate oxygen and to the possibility of incorporation into the framework Higher activity was observed, in general, with fresh catalysts synthesised by FP. The SG samples demonstrated a slightly better resistance to sulphur poisoning when considering the conversion decrease between the fresh and the poisoned samples, due to lower surface exposure. However, interesting data have been

A power unit constituted by a reformer section, a H2 purification section and a fuel cell stack is being tested c/o the Dept. of Physical Chemistry and Electrochemistry of Università degli Studi di Milano, on the basis of a collaboration with HELBIO S.A. Hydrogen and Energy Production Systems, Patras (Greece), supplier of the unit, and some sponsors (Linea Energia S.p.A., Parco Tecnologico Padano and Provincia di Lodi, Italy). The system size allows to cogenerate 5 kWe (220 V, 50 Hz a.c.) + 5 kWt (hot water at 65°C) as peak output. Bioethanol, obtainable by different non-food-competitive biomass, is transformed into syngas by a prereforming and reforming reactors couple and the reformate is purified from CO to a concentration below 20 ppmv, suitable to feed a proton exchange membrane fuel cell (PEMFC) stack that will be integrated in the fuel processor in a second step of the experimentation. This result is achieved by feeding the reformate to two water gas shift reactors, connected in series and operating at high and low temperature, respectively. CO

121ChemInform Abstract The primary alcohols (I) are converted to the aldehydes (II) by treatment with sodium hypochlorite in the presence of a piperidine-1-oxyl radical. Addition of a phase transfer catalyst to the reaction mixture leads to the formation of the corresponding carboxylic acids (III).