Cavaliere, S. ; Chevallier, L. ; Jones, D. ; Rozière, J. ; Bauer, A.FZJ* ; Hui, R.

2010

Abstract: Crystalline microspheres of 5 at.% Nb-TiO2 (anatase form) with a high specific surface area have been synthesized using a templating method using ionic interactions between the nascent inorganic structure and polyelectrolyte template. A core-shell arrangement is obtained, with a meso-macroporous core structure, and a mesoporous shell. The material has been investigated as catalyst support for polymer electrolyte membrane fuel cells. A uniform dispersion of Pt particles on the Nb-doped TiO2 support was obtained using a microwave method. The electrochemical properties of Pt deposited on TiO2 based microspheres were compared with those of commercial carbon supported Pt. Nb-TiO2 supported Pt shows promising electrochemical properties, comparable to those of Pt/C. Furthermore, Nb-TiO2 supported Pt demonstrated very high stability after 1000 voltammetric cycles, since 85% of the electroactive Pt area remained after the stability testing, while only 47% of the electroactive Pt area remained in the case of Pt supported on carbon. For the oxygen reduction reaction, the highest stability was again obtained for the Nb doped TiO2 based material even though the mass activity calculated at 0.9 V vs. RHE was slightly lower. The microsphere structured and mesoporous Nb-doped TiO2 is an appealing alternative to carbon support for high temperature PEM fuel cells.