An Alkaline-Acid Glycerol Electrochemical Reformer for Simultaneous Production of Hydrogen and Electricity

Abstract

This study shows the results, for the first time, of an glycerol alkaline-acid electrolyzer. Such a configuration allows spontaneous operation, producing energy and hydrogen simultaneously as a result of the utilization of the neutralization and fuel chemical energy. The electroreformer—built with a 20 wt% Pd/C anode and cathode, and a Na+-pretreated Nafion® 117—can simultaneously produce hydrogen and electricity in the low current density region, whereas it operates in electrolysis mode at high current densities. In the spontaneous region, the maximum power densities range from 1.23 mW cm−2 at 30 °C to 11.9 mW cm−2 at 90 °C, with a concomitant H2 flux ranging from 0.0545 STP m−3 m−2 h−1 at 30 °C to 0.201 STP m−3 m−2 h−1 at 90 °C, due to the beneficial effect of the temperature on the performance. Furthermore, over a chronoamperometric test, the electroreformer shows a stable performance over 12 h. As a challenge, proton crossover from the cathode to the anode through the cation exchange Nafion® partially reduces the pH gradient, responsible for the extra electromotive force, thus requiring a less permeable membrane.

Keywords

• glycerol
• hydrogen
• electrolysis
• alkaline-acid
• energy
• spontaneity