Bare and Doped Ti-oxides as Supports and Promoters for Electro-catalysts in Low Temperature Direct Methanol and Polymer Electrolyte Fuel Cells

摘要

Bare and doped Ti-oxides were prepared by using various synthesis routes and investigated in terms of structure, morphology and electrochemical properties for application as catalyst supports and promoters in low temperature direct methanol and polymer electrolyte fuel cells. A crystalline Anatase phase was obtained for most of the doped and undoped Ti-oxide supports after an air treatment in a range 300°- 600 °C. BET surface area varied as a function of the preparation route, the doping agent and the thermal treatment. A colloidal preparation route allowed to achieve crystalline materials with crystallite domain sizes smaller than 10 nm. BET surface area values of about 250 m2/g were obtained. Electrochemical tests showed that oxide supports were significantly more stable in terms of electrochemical corrosion than conventional carbon black supports used in fuel cells. Oxygen reduction reaction studies (ORR) showed a promoting effect under specific operating conditions and a significant performance enhancement.