Electrospun Nb-doped TiO₂ nanofiber support for Pt nanoparticles with high electrocatalytic activity and durability

This study explores a facile method to prepare an efficient and durable support for Pt catalyst of polymer electrolyte membrane fuel cell (PEMFC). As a candidate, Nb-doped TiO₂ (Nb-TiO₂) nanofibers are simply fabricated using an electrospinning technique, followed by a heat treatment. Doping Nb into the TiO₂ nanofibers leads to a drastic increase in electrical conductivity with doping level of up to 25 at. % (Nb_0.25Ti_0.75O₂). Pt nanoparticles are synthesized on the prepared 25 at. % Nb-doped TiO₂-nanofibers (Pt/Nb-TiO₂) as well as on a commercial powdered carbon black (Pt/C). The Pt/Nb-TiO₂ nanofiber catalyst exhibits similar oxygen reaction reduction (ORR) activity to that of the Pt/C catalyst. However, during an accelerated stress test (AST), the Pt/Nb-TiO₂ nanofiber catalyst retained more than 60% of the initial ORR activity while the Pt/C catalyst lost 65% of the initial activity. The excellent durability of the Pt/Nb-TiO₂ nanofiber catalyst can be attributed to high corrosion resistance of TiO₂ and strong interaction between Pt and TiO₂.