Electro-reforming of bioethanol produced by sugar fermentation on a Pt-Ni anodic catalyst supported on graphene nanoplatelets

Abstract

A study of the electro-reforming of bioethanol produced through sugar fermentation using a Pt-Ni supported on graphene nanoplatelets (Pt-Ni/GNPs) anodic catalyst is presented here. The physicochemical characterization of the anodic catalyst showed a good dispersion and small sizes of the metallic crystallite. Then, the evolution of the electrochemical activity over time of three bioethanol batches with different initial sugar concentrations of 150, 200 and 250 g·L−1 was explored in a Proton Exchange Membrane (PEM) electrolysis cell. A general growth in the ethanol concentration over time was observed for all the bioethanol batches, along with an improvement in the electrochemical activity, principally associated to ethanol oxidation reaction (EOR). Additionally, the presence of non-fermented sugar and other molecules formed during fermentation exhibited a negative contribution in the electrochemical activity. The bioethanol batch with an initial sugar concentration of 200 g·L−1 presented the best compromise between bioethanol production, fermentation time and electrochemical activity, achieving competitive current densities (∼285 mA·cm−2 at 1.2 V) and energy consumption values (21.6 kWh·kgH2−1 at 100 mA·cm−2) to those from other publications using synthetic ethanol-water solutions. These results demonstrated the interest of the used Pt-Ni/GNPs anodic catalyst for the renewable hydrogen production via direct electro-reforming of liquid biofuels.