Doped TiO2 aerogels as alternative catalyst supports for proton exchange membrane fuel cells: A comparative study of Nb, V and Ta dopants

Christian Beauger (1) , Laetitia Testut (1) , Sandrine Berthon-Fabry (1) , Frédéric Georgi (2) , Laure Guétaz (3, 4)

1 PERSEE - Centre Procédés, Énergies Renouvelables, Systèmes Énergétiques
2 CEMEF - Centre de Mise en Forme des Matériaux
3 LIG - Laboratoire d'Informatique de Grenoble
4 LITEN - Laboratoire d'Innovation pour les Technologies des Energies Nouvelles et les nanomatériaux

Nb, Ta and V-doped TiO2 aerogels and xerogels have been synthesized as possible new alternatives to carbon blacks for Proton Exchange Membrane Fuel Cells catalyst supports. A comparative study of different dopants was realized in a single study. Nb, Ta and V showed different behaviors with respect to the final material structure and morphology, composition and electronic conductivity. They are all prone to surface segregation, to different extents. V-doped TiO2 apart, the rutile structure could only be obtained after calcination in a reducing atmosphere at 800 °C for Nb or Ta-doped TiO2. The electronic conductivity exhibited a maximum at 10 at.% for Nb and Ta, 5 at.% for V. Nb revealed to be the most appropriate dopant to increase the electronic conductivity of TiO2, followed by Ta and V. 4 to 5 orders of magnitude were gained after Nb doping for xerogels conductivity to reach almost 0.1 S cm−1. The role of point defects was discussed to account for phase transition and evolution of conductivity.

Mots clés: Doped titania aerogel; Morphology; Conductivity

Domaines: Sciences de l'ingénieur [physics]; Energétique

Christian Beauger, Laetitia Testut, Sandrine Berthon-Fabry, Frédéric Georgi, Laure Guétaz. Doped TiO2 aerogels as alternative catalyst supports for proton exchange membrane fuel cells: A comparative study of Nb, V and Ta dopants. Microporous and Mesoporous Materials, 2016, 232, pp.109-118. ⟨10.1016/j.micromeso.2016.06.003⟩. ⟨hal-01327894⟩