Hollow Co nanoparticle/carbon nanotube composite foam for efficient electrocatalytic hydrogen evolution

Abstract

The electrochemical hydrogen evolution reaction (HER) requires highly efficient electrocatalysts with durable and stable performance. In this work, multiwalled carbon nanotubes (MWCNTs) are employed as electrocatalyst carriers, polystyrene microspheres as templates, chitosan as a nitrogen-doped carbon (N–Carbon) source, and cobalt nitrate as a cobalt source to manufacture hollow Co nanoparticle and N–carbon modified CNT (Co/NCNT) composite foam as highly efficient electrocatalysts with durable and stable performance. This composite foam not only has a fast electron transfer rate but also contains more exposed intact sites and ion transport channels, making ion storage and movement easier. In addition, hollow Co nanoparticles (NPs) enhanced the catalyst activity and N–Carbon and MWCNTs enhanced the electrical conductivity of the carbon matrix. The coupling between the hollow Co NPs, N–Carbon, and MWCNTs enhances the electrocatalytic performance of the electrocatalyst in the HER. Compared with other electrocatalysts, the Co/NCNT exhibits lower overpotential (20 mV) at a current density of 10 mA cm⁻², lower Tafel slope (27.53 mV dec⁻¹) and stronger cycling durability (2000 cycles) in 1 M KOH. The composite foam developed here may be a potential high-performance HER catalyst.