V–P–O compound encapsulated palladium nanoparticles supported on carbon nanotubes as a methanol-tolerant oxygen reduction electrocatalyst

Abstract

Palladium (Pd) nanoparticles encapsulated by the vanadium–phosphorus–oxygen (V–P–O) compound were synthesized and decorated on carbon nanotubes (Pd@V–P–O/CNT) through an oleylamine-mediated method stabilized with trioctylphosphine. Electrochemical measurements indicated that the Pd@V–P–O/CNT exhibited comparative catalytic activity towards the oxygen reduction reaction (ORR) compared with commercial Pd/C and Pd nanoparticles supported on carbon nanotubes (Pd/CNT), but with a significantly enhanced methanol tolerance. The vanadium/phosphorus mixed oxide shell on the Pd nanoparticles could effectively block the active Pd sites from methanol oxidation without obviously decreasing the catalytic activity towards the ORR process, implying that Pd@V–P–O/CNT might be a promising alternative to the Pt electrocatalyst applied in direct methanol fuel cells.