Magneli phase titanium sub-oxide conductive ceramic TiO as support for electrocatalyst toward oxygen reduction reaction with high activity and stability.

Magneli phase titanium sub-oxide conductive ceramic TiO was used as the support for Pt due to its excellent resistance to electrochemical oxidation, and Pt/TiO composites were prepared by the impregnation-reduction method. The electrochemical stability of TiO was investigated and the results show almost no change in the redox region after oxidation for 20 h at 1.2 V (vs NHE) in 0.5 mol/L HSO aqueous solution. The catalytic activity and stability of the Pt/TiO toward the oxygen reduction reaction (ORR) in 0.5 mol/L HSO solution were investigated through the accelerated aging tests (AAT), and the morphology of the catalysts before and after the AAT was observed by transmission electron microscopy. At the potential of 0.55 V (vs SCE), the specific kinetic current density of the ORR on the Pt/TiO is about 1.5 times that of the Pt/C. The LSV curves for the Pt/C shift negatively obviously with the half-wave potential shifting about 0.02 V after 8000 cycles AAT, while no obvious change takes place for the LSV curves for the Pt/TiO. The Pt particles supported on the carbon aggregate obviously, while the morphology of the Pt supported on TiO remains almost unchanged, which contributes to the electrochemical surface area loss of Pt/C being about 2 times that of the Pt/TiO. The superior catalytic stability of Pt/TiO toward the ORR could be attributed to the excellent stability of the TiO and the electronic interaction between the metals and the support. [ABSTRACT FROM AUTHOR]