Control of surface area and conductivity of niobium-added titanium oxides as durable supports for cathode of polymer electrolyte fuel cells

Abstract

Niobium-added titanium oxide is a promising candidate as a substitute carbon support for cathodes of PEFCs. Nb-added TiO2 can act as a support for platinum nanoparticles to enhance the oxygen reduction reaction (ORR) activity and durability under acidic conditions. Nb-added TiO2 supports with the desired surface area (10–130 m2 g−1) and conductivity (10−7–10−2 S cm−1) were prepared by changing the amount of Nb and the heat treatment conditions. First, we conducted a systematic investigation with changes in the amount of niobium addition, heat-treatment temperature, and time under a pure hydrogen atmosphere to reveal the physicochemical factors that govern the surface area and conductivity. Finally, we successfully proposed a procedure to prepare highly durable Nb-added TiO2 supports with the desired surface area and conductivity by controlling the amount of niobium addition, heat-treatment temperature, and time under hydrogen. The charges of the double layer were almost unchanged after 5000 cycles of an accelerated durability test (ADT).

Keywords

• Conductive electrodes
• Support cathode catalysts
• Polymer electrolyte fuel cells
• Carbon-free support