(48b) Electricity Storage in Biofuels: Selective Electro-Catalytic Reduction of Levulinic Acid to Valeric Acid Or ?-Valerolactone

For a foreseeable future, the most
desirable energy-carriers for transportations remain liquid hydrocarbon fuels,
because of their ease, speed and safety of fueling, their efficient
distribution network, and their very high energy densities.  Direct storage
of electrical energy in high energy-density liquid transportation fuels
(electro-biofuels) using electro-catalytic (flow) cell devices shows unique
characteristics as compared to other electricity storage devices and provides a
promising and sustainable way to store renewable electricity. In this
presentation, we reports an effective approach to electricity storage in
biofuels via selective electro-catalytic reduction of levulinic
acid (LA) to high energy-density valeric acid (VA) or
γ-valerolactone (gVL)
on a non-precious Pb electrode (99.9%) in a single
polymer electrolyte membrane electro-catalytic (flow) cell device, which has
demonstrated very high yield of VA (>90%), high Faradaic efficiency
(>86%), promising electricity storage efficiency (70.8%) and low electricity
consumption (1.5 kWh L^-1_VA). Applied potential and
electrolyte pH were found to accurately control the reduction products: lower
over-potentials favor the production of gVL, and
higher over-potentials facilitate the formation of VA. The effect of molecular
structure on electro-catalytic reduction of ketone and aldehyde groups of
biomass-derived compounds and our current research on integrated
electro-catalytic conversion of LA and formic acid to valeric
acid over nanostructured metallic catalysts will also be presented. This
?electro-biofuel? technique will have potential to alleviate our long-time
addiction to using non-renewable petroleum sources for production of
transportation fuels.