(591e) Low Temperature and High Efficiency Biomass Fuel Cell and Bio-Hydrogen Production

A novel fuel cell which can directly use native polymeric biomasses, such as starch, cellulose, lignin, and even switchgrass and wood powders will be discussed. This fuel cell combines some features of solar cells, fuel cells, and redox flow batteries. Specifically, an oxidation/reduction ion pair, such as Fe²⁺/Fe³⁺, or polyoxomatelate, are used as catalyst to oxidize biomass by either absorbing solar light or heat energy. The power density of the solar-induced hybrid fuel cell powered with raw biomass could reach ~50 mW/cm². Unlike most cell technologies that are sensitive to impurities, the cell reported in this study is inert to most organic and inorganic contaminants present in the fuels. The fuel cell is completely noble metal free. The similar fuel cell system can also be converted to electrolysis cell for hydrogen production at low temperature using native biomass directly. Either polyoxometalate (POM) or FeCl₃ was used as the catalysts and charge transfer agents in anode. Over 90% Faraday efficiency was achieved. In a thermal insulation reactor, the heat energy can be maintained at a very low stage for continuous operation. Compared to the best alkaline water electrolysis reported in literature, the electrical energy consumption could be 40% lower with novel lignin electrolysis method. Our results suggest that POM or FeCl₃ mediated electrolysis process can significantly reduce the electrolysis energy consumption in hydrogen production and, simultaneously, depolymerize lignin to low molecular weight value-added aromatic chemicals.