Ruthenium-reduced Amorphous Tungsten Oxide Catalyst

This invention relates to improved catalysts for reacting carbon monoxide and carbon dioxide with hydrogen to form methane and water. More specifically, this invention relates to a multi-component catalyst containing ruthenium, with or without platinum, which catalyst is beneficated with a specific tungsten oxide.

Heretofore, many kinds of metallic catalyst have been utilized in various supported and nonsupported forms to promote the reaction of carbon monoxide and carbon dioxide with hydrogen to form methane and water. These reactions are the basis of the standard Fischer-Tropsch reaction for the synthesis of hydrocarbons from carbon monoxide or carbon dioxide and hydrogen. In addition, these same reactions are employed in the clean-up reformer product gases before introduction into fuel cells, or before nitrogenation in ammonia synthesis plants. Most of the catalysts used in these reactions are primarily nickel-based and operate at relatively high temperatures, about 400C. Further, they do not selectively methanate CO in the presence of CO In addition, they require a relatively large reactor size, and the reaction conditions are relatively severe.

We have discovered catalysts that can methanate carbon monoxide and/or carbon dioxide by reaction with hydrogen. These catalysts include ruthenium met als having minor amounts of reduced amorphous tungsten oxide admixed therewith. The ruthenium may be used alone or in mixtures and with platinum. We have discovered, unexpectedly, that the minor amounts of reduced amorphous tungsten oxide admixed with the ruthenium have a synergistic effect in a methanation process. In addition, the methanation activity is quite unexpected in view of the fact that tests show that there is no net effective carbon monoxide chemical reaction in an operating fuel cell using such materials under electrical potential as electrodes. These catalysts could also find utility as fuel cell electrodes and hydrocarbon conversion catalysts.

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