Electrochemical Reactions in a DMFC under Open-Circuit Conditions

Abstract

Gas evolution, principally consisting of carbon dioxide and hydrogen, was observed in the anode flow field of a direct methanol fuel cell (DMFC) running under open-circuit conditions and at low oxygen flow rates. This finding is contrary to conventional wisdom that electrochemical reactions cease as an external load is removed. The mechanism leading to this peculiar phenomenon is explained theoretically and confirmed experimentally.