Nanostructured molybdenum Phosphide/N-Doped carbon nanotube-graphene composites as efficient electrocatalysts for hydrogen evolution reaction

Abstract

Uniformly dispersed ∼10 nm MoP nanoparticles on N-doped carbon nanotube and graphene composite (NCNT-NGR) support are synthesized via a simple temperature-programmed reduction method for electrocatalytic hydrogen evolution reaction (HER). The NCNT-NGR support is composed of well-intercalated carbon nanotube (CNT) between graphene layers, resulting in suppressed CNT bundling and graphene re-stacking, hence providing a large surface area. The prepared MoP/NCNT-NGR composite exhibits high HER activity than control catalysts (MoP/NCNT, MoP/NGR, and bare MoP) with a small benchmark overpotential of 100 mV to drive 10 mA/cm2 and an improved Tafel slope of 44 mV/dec in an acidic medium. It also exhibits excellent stability for 1000 potential cycles and in a 10-h chronoamperometry test. Such a HER performance arises from synergy between highly active MoP nanoparticles and the large surface area/highly conductive NCNT-NGR support.