Improved performance of direct methanol fuel cells by anodic treatment

Anodic treatment of direct methanol fuel cell single cells was carried out at anode potentials of 0.1, 0.4, 0.7, and 1.0 V. An increase in maximum power density by 48% was achieved after anodic treatment at 0.7 V. Electrochemical impedance spectroscopy showed that the methanol electro-oxidation activity of the PtRu catalyst was promoted by the anodic treatment. Oxidation states of Ru changed from Ru metal (43%) and RuO2 (57%) to RuO2 (33%) and RuOxHy (67%), which were studied by X-ray photoelectron spectroscopy. The results showed that the formation of RuOxHy occurred at a potential range of 0.4-0.7 V. (c) 2006 The Electrochemical Society.