(22c) H2 Generation From Aqueous Methanol Electrolysis Using Hybrid Electrocatalysts Based Electrodes

Methanol electrolysis offers an elegant path to generate pure H₂ at lower temperatures (5-120ºC), which subsequently can be used in a low power fuel cell. This process appears promising as it typically uses lower temperatures and voltages for H₂ generation as compared with the direct oxidization of methanol in a fuel cell. This work describes the fabrication of different hybrid electrode materials and their utilization in aqueous methanol electrolysis for H₂ generation. The methanol electrolysis was performed in an electrolytic cell containing a membrane electrode assembly, which comprised of a proton conducting polymeric membrane, for instance, Nafion perfluorosulfonic acid polymer, sandwiched between a catalytic anode (platinum/chromium) and a cathode (platinum). In the preliminary experiments, hybrid electrodes were fabricated wherein a proton conduction membrane (Nafion 117) was sputter coated with Pt on one side and bimetallic electrode (Pt/Cr) on the other side. The thickness of the electrode was varied by controlling the sputtering current and time. The electrodes were characterized using SEM/EDX to determine their morphology and composition. Additional efforts focusing on the use of polyamidoamine (PAMAM) dendrimers as hosts/templates for catalyst nanoparticles are underway, which presumably lowers the loadings of nobel metal catalyst. The acidified Nafion membrane coated with different electrodes were contacted with an aqueous methanol solution on the anode side in the electrochemical cell and I-V characteristics of the cell were measured. During electrolysis of aqueous methanol, the gas samples were analyzed using a gas chromatograph (GC) equipped with chrompak column and thermal conductivity detector. I-V characteristics and SEM/EDX analysis of hybrid electrodes, and H₂ volume generation from aqueous methanol electrolysis will be presented.