Polyacrylonitrile-based 3D N-rich activated porous carbon synergized with Co-doped MoS2 for promoted electrocatalytic hydrogen evolution

Abstract

MoS2 is a promising electrocatalyst for the hydrogen evolution reaction (HER), but it is limited by its own agglomeration, low conductivity, and surface inertness. In this study, we report a well-organized 3D hybrid structure of N-rich active porous carbon (CN) synergized with Co-doped molybdenum disulfide (Co-MoS2@CN) for promoted electrocatalytic hydrogen evolution. MoS2 nanosheets were grown vertically on CN and the pore structure was improved, which exposed abundant edge active sites. The N-rich graphite structure and abundant pore structure of CN enhanced the electron transfer ability and stability of the 3D hybrid structure. Meanwhile, doping of Co atoms optimized the catalytic activity of the in-plane sulfur sites and induced a partial transition from 2H-MoS2 to 1 T-MoS2. The resulting Co-MoS2@CN 3D hybrid structure exhibited excellent HER electrocatalytic performance, had a current density of 10 mA cm−2 in a 0.5 M H2SO4 aqueous solution by an overpotential of 137 mV, and showed excellent stability in a 24 h HER test. DFT calculations confirmed that the heterogeneous interface constructed by CN and Co-MoS2 effectively optimized Gibbs free energy (ΔGH*) of the MoS2 hydrogen adsorption site and enhanced the interfacial electron transfer capacity, which ensured rapid HER kinetics during the electrocatalytic process.