Clean hydrogen generation through the electrocatalytic oxidation of ethanol in a Proton Exchange Membrane Electrolysis Cell (PEMEC): Effect of the nature and structure of the catalytic anode

Abstract

The electrocatalytic oxidation of ethanol was investigated in a Proton Exchange Membrane Electrolysis Cell (PEMEC) working at low temperature (20°C) on several Pt-based catalysts (Pt/C, PtSn/C, PtSnRu/C) in order to produce very clean hydrogen by electrolysis of a biomass compound. The electrocatalytic activity was determined by cyclic voltammetry and the rate of hydrogen evolution was measured for each catalyst at different current densities. The cell voltages UEtOH were recorded as a function of time for each current density. At 100 mA cm−2, i.e. 0.5 A with the 5 cm2 surface area PEMEC used, the cell voltage did not exceed 0.9 V for an evolution rate of about 220 cm3 of hydrogen per hour and the electrical energy consumed was less than 2.3 kWh (Nm3)−1, i.e. less than one half of the energy needed for water electrolysis (4.7 kWh (Nm3)−1 at UH2O = 2 V). This result is valid for the decomposition of any organic compound, particularly those originated from biomass resource, provided that their electro-oxidation rate is sufficient (>100 mA cm−2) at a relatively low cell voltage (Ucell < 1 V) which necessitates the development of efficient electrocatalysts for the electrochemical decomposition of this compound.