In Situ Coupling of CoP Polyhedrons and Carbon Nanotubes as Highly Efficient Hydrogen Evolution Reaction Electrocatalyst

Abstract

Hydrogen evolution reaction (HER) from water electrolysis is an attractive technique developed in recent years for cost-effective clean energy. Although considerable efforts have been paid to create efficient catalysts for HER, the development of an affordable HER catalyst with superior performance under mild conditions is still highly desired. In this work, metal-organic frameworks (MOFs)-templated strategy is proposed for in situ coupling of cobalt phosphide (CoP) polyhedrons nanoparticles and carbon nanotubes (CNTs). Due to the synergistic catalytic effect between CoP polyhedrons and CNTs, the as-prepared CoP-CNTs hybrids show excellent HER performance. The resultant CoP-CNTs demonstrate excellent HER activity in 0.5 m H₂ SO₄ with Tafel slope of 52 mV dec^-1 , small onset overpotential of ≈64 mV, and a low overpotential of ≈139 mV at 10 mA cm^-2 . Additionally, the catalyst also manifests superior durability in acid media. Considering the structure diversity of MOFs, the strategy presented here can be extended for synthesizing other well-defined metal phosphides-CNTs hybrids, which may be used in the fields of catalysis, energy conversion and storage.

Keywords: carbon nanotubes; cobalt phosphide polyhedrons; electrocatalysis; hydrogen evolution reaction.