Preparation of TiO2:TiN composite nanowires as a support with improved long-term durability in acidic medium for polymer electrolyte fuel cells

Abstract

A TiO₂:TiN composite nanowire-supported catalyst is prepared for oxygen reduction activity in polymer electrolyte fuel cells (PEFCs). The TiO₂:TiN composite nanowire supported catalyst shows improved catalytic stability compared to carbon supported Pt. Field emission scanning electron microscopy, transmission electron microscopy, X-ray photoelectron spectroscopy, X-ray diffraction, Brunauer–Emmett–Teller and conductivity measurements have been used to demonstrate morphological effects, oxidation states and crystal structures along with surface area and electrical properties, which play a vital role in enhancing the oxygen reduction reaction. The optimized composition of the TiO₂:TiN composite nanowire supported catalyst leads to improved catalyst durability even after 10 000 potential cycles. In PEFCs, the Pt/TiO₂:TiN nanowire composite increases corrosion stability and retains 67% of initial cell performance even after 3000 potential cycles between 1 and 1.5 V vs. a dynamic hydrogen electrode as compared to a carbon supported catalyst. After AST, the samples are characterized for the assessment of degradation of fuel cell performance.