Enhanced Oxygen Reduction Reaction Activity and Durability of TiO2C Modified PtAu Catalysts driven by atmosphere induced surface segregation

C.W. Liu, C.M. Lai, J.N. Lin, L.D. Tsai, K.W. Wang
National Central University, TW

Keywords: Pt-Au/C catalysts, TiO2, H2, air, oxygen reduction reaction (ORR), accelerated durability test (ADT)

Summary:

In this study, we demonstrate a facile chemical method to prepare titanium dioxides mixed with carbon (TiO2C) modified Pt75Au25 catalysts for ORR in order to overcome the carbon corrosion and the dissolution of Pt atoms at the carbon support surface during long-term test. The 35 wt % of Pt75Au25 catalysts supported on TiO2C are reduced by isopropyl alcohol and denoted as PtAu/TiO2C. For further promotion of the electrochemical performance, the as-prepared catalysts are heat treated at air or hydrogen (H2) atmosphere and designated as PtAu/TiO2C(Air) and PtAu/TiO2C(H2), respectively. The ORR activity of TiO2C modified Pt75Au25 catalysts are promoted by post heat treatment at air atmosphere. After accelerated durability test (ADT) of 1700 cycles, the ORR activity of PtAu/TiO2C(Air) catalysts with the size of 4.8 nm is 3 times higher than that of the commercial Pt/C. The enhancement of ORR activity is attributed to air-induced Pt surface segregation.