A Kinetics Analysis of Methanol Oxidation under Electrolysis/Fuel Cell Working Conditions

摘要

The production of clean hydrogen for PEMFC was carried out by the electrochemical decomposition of methanol inside a DMFC hardware working as a PEMEC at different temperatures (25 to 85°C) and several methanol concentrations (0.1 to 10 M). Using the Pt/C cathode where hydrogen evolution does occur, as a reference electrode, it was possible to derive the methanol anode potential, E_(meth), from the cell voltage U_(cell)(j) vs. the current density j, of the electrolysis cell corrected from ohmic losses. A Tafel plot analysis of E_(meth) vs. Ln (j) allowed us to estimate the cell resistance (R_e ～ 0.75 Ω at 85°C), the transfer coefficient (α ～ 0.5-0.6) and the heat of activation (ΔH~* ～ 50-60 kJ mole~(-1)) for methanol oxidation.