Nanotechnology makes biomass electrolysis more energy efficient than water electrolysis

Abstract

The energetic convenience of electrolytic water splitting is limited by thermodynamics. Consequently, significant levels of hydrogen production can only be obtained with an electrical energy consumption exceeding 45 kWhkg -1 H2. Electrochemical reforming allows the overcoming of such thermodynamic limitations by replacing oxygen evolution with the oxidation of biomass-derived alcohols. Here we show that the use of an original anode material consisting of palladium nanoparticles deposited on to a three-dimensional architecture of titania nanotubes allows electrical energy savings up to 26.5kWh kg-1 H2 as compared with proton electrolyte membrane water electrolysis. A net energy analysis shows that for bio-ethanol with energy return of the invested energy larger than 5.1 (for example, cellulose), the electrochemical reforming energy balance is advantageous over proton electrolyte membrane water electrolysis. © 2014 Macmillan Publishers Limited. All rights reserved.