Fuel cells for chemicals and energy cogeneration

Fuel cells (FCs) are mainly applied for electricity generation. This paper presents a review of specific FCs with ability to produce useful chemicals at the same time. The chemical cogeneration processes have been classified according to the different types of fuel cells. Thus, it is shown that a flow alkaline FC (AFC) is able to produce hydrogen peroxide. In aqueous acid or neutral FCs, hydrogenations, dehydrogenations, halogenations and oxidations, together with pollution abatement solutions, are reported. Hydrogen peroxide and valuable organic chemicals can also be obtained from polymer electrolyte FCs (PEFCs). A phosphoric acid FC (PAFC) allows the selective oxidation of hydrocarbons and aromatic compounds, and the production of industrial compounds such as cresols. Molten salt FCs (similar to molten carbonate or MCFCs) can be applied to obtain acetaldehyde with high product selectivity from ethanol oxidation at the anode. Solid oxide FCs (SOFCs) are able of chemical cogeneration of valuable industrial inorganic compounds such as nitric oxide with high yields. Although the number of related papers in the literature is small, the potential economic interest of this emergent field, related to the recent commercial development of fuel cells, is demonstrated in some cases, and the corresponding results encourage the development of FCs with electrocogeneration of useful chemicals with high added value and electricity.