Generation of electricity with fuel cell using alcohol fuel

Abstract

In this method, a lower alcohol is oxidized directly (i.e. without reformation) to CO.sub.2 +H.sub.2 O at the anode of a fuel cell, and a reducible gas (e.g. air or O.sub.2) is reduced at the cathode. High, reasonably constant current densities at low over-voltages can be obtained. The electrolyte is preferably an acidic solid polymer electrolyte, and the anode comprises, as the electrocatalyst, a combination of a Group VIII noble metal with gold having significant Au (111) character. The (111) face of gold crystals (preferably crystals in the size range of about 4 to 15 nm) have been found to be specific for oxidation of intermediate alcohol oxidation products (CO, CHO, COH, HCHO, CH.sub.3 CHO, etc.) to CO.sub.2 or CO.sub.2 +H.sub.2 O. Thus, the combination of a Group VIII metal such as Pt with Au (111) avoids 'poisoning' of the Pt by these intermediate products. Some protection against such 'poisoning' is also provided with Au (110), but Au (100) and polycrystalline gold are not considered useful in the electro-oxidation of lower alcohols (particularly methanol and ethanol). If the alcohol 'fuel' is methanol, the combination of Group VIII noble metal and Au (111) should be microscopically homogeneous (e.g. Pt/Au cubo-octahedral crystals with a high level of (111) faceting), but if the 'fuel' is ethanol, the Group VIII noble metal and the Au (111) can be combined in various ways, including macroscopic homogeneous mixtures and heterogeneous blends.