Polypyrrole Effect on Carbon Vulcan Supporting Nickel-Based Materials Catalyst During Methanol Electro-Oxidation

The catalyst in methanol oxidation plays a pivotal role in direct fuel cell reaction. The aim of this work is to study the influence of polypyrrole polymer (PPy) added in the carbon Vulcan support for the methanol oxidation reaction. The catalytic active phase synthesized was nickel-based materials, which have been demonstrated to exhibit remarkable chemical stability in alkaline solutions. The metallic-active phase was supported at the PPy-carbon Vulcan matrix. PPy is a conductor polymer and the research of electric conduction in synergy with a carbon Vulcan and a Ni catalyst is scarcely reported. The morphology characterization of composite catalytic material was carried out by XRD, XPS, and TEM techniques. In turn, the catalytic activity of the composite is characterized by means of cyclic voltammetry (CV). Electrochemical impedance spectroscopy (EIS) showed the influence of PPy on the charge transfer resistance (Rch. t.). The results indicate that a decrease in the Rch. t. was associated with an increase in methanol oxidation; therefore, higher amounts of charge transfer is produced. Furthermore, the DEMS technique corroborates the EIS results, confirming elevated conversion toward oxidation products. In turn, the selectivity of the composite-catalytic support on the methanol oxidation was elucidated using in situ Raman spectroscopy.