A hybrid Pt/NbO/CNTs catalyst with high activity and durability for oxygen reduction reaction in PEMFC

Abstract

To improve the kinetics and durability of Pt-based electrodes toward the oxygen reduction reaction (ORR), high electroactive and stable catalysts were synthesized by depositing Pt over niobium oxide (NbO) supported on commercial multi-wall carbon nanotubes (CNTs). The Pt/NbO/CNTs, exhibits excellent electroactivity and stability toward ORR, reaching a high electroactivity of 57 mA mgPt−1, higher than the Pt/CNTs and commercial Pt/C (20% Pt/C HiSPEC™). Moreover, the developed Pt/NbO/CNTs demonstrated outstanding durability under accelerated stress testing (AST) according to load cycling and startup/shutdown stability protocols. Proton exchange membrane fuel cells (PEMFC) tests with an MEA fabricated using Pt/NbO/CNTs showed excellent performance, with a low Pt loading down to 0.15 mg cm−2, achieving a maximum power density of 772 mW cm−2. Furthermore, a short-term durability test in PEMFC demonstrated only a 4% loss on the maximum power density at 80 °C. The superior electrocatalytic activity and durability of Pt/NbO/CNTs can be ascribed to the anchoring effect of Pt nanoparticles over the NbO/CNTs hybrid support, showing that the developed Pt/NbO/CNTs is a promising durable electrocatalyst for PEMFC applications.