Graphene functionalization with metallic Pt nanoparticles: A path to cost-efficient H₂ production in microbial electrolysis cells

Platinum is one of the most widely used catalysts in the cathode of Microbial Electrolysis Cells (MECs) to overcome the relatively slow kinetics of hydrogen evolution, even though it is not economically feasible on a large scale. This work aims at developing, applying, characterizing, and optimizing two novel Pt-functionalized inks with promising characteristics: Pt@rGO based on reduced graphene oxide and Pt@Graphitene based on a home-made material named Graphitene, which showed improved performance at a lower cost. The Pt-functionalized materials were deposited on carbon cloth and used as cathode electrode in a single chamber MEC. These materials provided 47% increase in Pt functionalization over commercial inks. Moreover, surface areas of 10.76 m2/g and 24.40 m2/g and electroactive areas of 0.10 cm2/cm2 and 0.16 cm2/cm2 were determined for Pt@Graphitene and Pt@rGO, respectively, a difference caused by structural defects in the case of the Pt@rGO, which slightly improved its performance compared to Pt@Graphitene. Thus, the experimental results reached ca. 0.8 mA/cm2, a 43% higher intensity than that obtained using conventional commercial inks.