Vanadium nitride nanofiber membrane as a highly stable support for Pt-catalyzed oxygen reduction reaction

Carbon-based nanomaterials are frequently used as a support for proton exchange membrane fuel cell (PEMFC) catalysts, due to their high electrical conductivity and large surface area; however, the limited long-term stability of carbon-based catalysts under PEMFC operation causes huge problems in practical applications. Here we report the use of vanadium nitride (VN) nanofiber membrane as a highly durable catalyst support for oxygen reduction reaction (ORR). Nanofibrous VN was prepared using a simple electrospinning process, followed by sequential heat treatments in air and NH3. The NH3 treatment temperature affected the crystallinity as well as the crystal size of VN, which ultimately affected the catalytic ORR activity of Pt-decorated catalysts. The optimized Pt/VN catalysts exhibited excellent ORR activity and durability in acid electrolyte. Much higher durability of Pt/VN than Pt/C was verified by chrono-amperometry analysis. Density functional theory (DFT) calculations provided further evidence of the strong interaction of Pt and VN, which contributed to the high stability of the catalyst.