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Reactions between hydrogen and carbon monoxide can lead to a variety of useful products depending on catalytic processes. Methanation is one of the most important processes, because it can upgrade the heat value of gas and reduce the carbon monoxide content of town gas from coal1. In the past several decades, methanation has been investigated extensively, the reaction over a nickel catalyst was first reported by Sabatier and Senderens in the beginning of this century. Since then, nickel catalyst has been studied widely by many scientists because of its high activity and selectivity as well as its low cost2. But nickel catalyst is sensitive to sulphur poison. To reduce the cost for the desulphurization, sulphur resistant molybdenum catalysts for methanation have received more attention in recent years, although they have only modest activity and need higher reaction temperature. Ultrafine particle (aerogel) catalyst is of, in general, higher activity as reported by Pajonle3, the ultrafine Mo/Al203 catalysts for methanation are prepared with supercritical drying.

Aerogel provides a unique very highly divided materials that can find more important applications in the ever growing domain of catalysis. They can be a component in solid superacid catalysts as Yamaguchi recently pointed out1. In particular, metal — on supported catalysts prepared under this form are very attractive since the sol — gel step permits one “to pour the metal out as a thin film or in any shape that is wanted” accord to Droege2. At the macro — scopic level, aerogels present a monodisperse distribution of particle dimensions which can be reorganized into “dynamic” cluster which are then easily fluidized so that their uses in real conditions are now envisaged and not only restricted at the laboratory scale. At the microscopic level, the mixed aerogels of their parent gels represent very homogeneous combinations originating from chemical interactions at the molecular scale in the liquid phase (or dispersed in a liquid phase) that can be viewed as “frozen” at the solid state. Aerogels are, in this respect, a sort of a three dimensional dry picture of the sol — gel product with all their catalytic potentialities intact and available for revelations. Catalysis continues as a major industrial application for molybdenum. A few researchers investigated the characterization of the catalyst diameter to determine the genesis and properties of the active sites. because it is too difficult to prepare sol — gel product on Mo compounds aerogel from (NH4)6Mo7O24 3. In this paper, we will discuss the Mo compound aerogel and its methanation.

The natural abundance 13C/12C ratio of methane from anoxic marine and freshwater sediments in temperate climates varies seasonally. Carbon isotopic measurements of the methanogenic precursors, acetate, and dissolved inorganic carbon from the marine sediments of Cape Lookout Bight, North Carolina have been used to determine the sources of the seasonal variations at that site. Movement of the methanogenic zone over an isotopic gradient within the dissolved CO2 pool appears to be the dominant control of the methane 13C/12C ratio from February to June. The onset of acetoclastic methane production is a second important controlling process during mid-summer. An apparent temperature dependence on the fractionation factor for CO2 reduction may have a significant influence on the isotopic composition of methane throughout the year.

Typically, in the heterogeneously catalyzed hydrogenation of carbon monoxide, copper-based catalysts are very selective for the synthesis of methanol, while cobalt-based catalysts exhibit Fischer-Tropsch activity with high selectivity to hydrocarbons. Mixed copper-cobalt catalysts have been reported to show, in various degrees [1–4], selectivity for higher alcohol formation. Of particular interest are the copper-cobalt catalysts developed by Sugier and co-workers [3,4] at the Institut Francais du Petrole (IFP). Most of these catalysts contain aluminum, chromium or zinc, and small amounts of alkali, so that their composition corresponds to that of alkalized conventional copper-based methanol synthesis catalysts modified by the addition of cobalt. With these catalysts, high yields of higher alcohols were obtained under methanol synthesis conditions, and, in contrast with other copper-cobalt systems [1–2], there was no appreciable methanation, and little [3] or moderate [4] formation of higher hydrocarbons.

The increasing demand of energy has renewed interest in catalytic production of hydrocarbons from carbon monoxide and hydrogen. One notable aspect of many Fischer-Tropsch catalysts thus far utilized has been the low dispersion of the active metal components1. Recent work suggests that the specific activity in methanation reaction depends on one hand on the particle size and on the other hand on the nature of the support2. In constrast to methanation, much less seems to be known about these effects in Fischer-Trospch conditions 3. In this context we have carried out studies of the catalytic properties of transition metal carbonyl complexes anchored on a peculiar inorganic matrix, namely a faujasite-type zeolite. A zeolite is a crystalline aluminosilicate with a regular pore structure making the internal surface available for adsorption and catalysis (Figure 1). The framework structure is constituted by corner-linked tetrahedra of A10 4 – and SiO4. The charge balance implies the presence of mono- and/or polyvalent cations 4,5. Earlier work from this laboratory 6 has shown that the adsorption of MO(CO)6, Re2(CO)10 and Ru3(CO)12 into an HY faujasite can occur. Subsequent thermal treatments lead either to ions (Mo) or to metal particles (Re, Ru) in agreement with the redox properties of the zeolite.

For the production of synthetic natural gas (SNG), oxygen and steam have been proposed to gasify coal in first- and second-generation coal gasification processes. Because of the high capital cost associated with oxygen and steam production, efforts have been made to reduce or eliminate the oxygen and steam requirements and to reduce or eliminate the shift and methanation steps normally required to upgrade the Btu content of the produced gas.