Ultralight porous carbon loaded Co-doped MoS2 as an efficient electrocatalyst for hydrogen evolution reaction in acidic and alkaline media

Abstract

Molybdenum disulfide (MoS2) has a Gibbs free energy comparable to platinum (Pt), suggesting it can replace Pt as a hydrogen evolution reaction (HER) catalyst. However, the shortcomings of the restricted number of MoS2 active sites and poor intrinsic electrical conductivity have resulted in impeding its widespread application. In this work, Co/MoS2@NPC electrocatalyst was prepared by using nitrogen-doped porous carbon (NPC) as a substrate material, and then hydrothermally anchoring cobalt-doped molybdenum disulfide (Co-doped MoS2) on the substrate. Co/MoS2@NPC was subsequently applied to hydrogen evolution reaction in acidic and alkaline media. It was found that the overpotential of 0.2Co/MoS2@NPC was only 139 mV for HER at 10 mA cm−2 with a Tafel slope of 69 mV dec−1 in acidic medium; while in alkaline medium, its overpotential was 163 mV with a Tafel slope of 106 mV dec−1, and it operated stably over 10 h. The superior HER performance may be related to the point that NPC as a substrate can uniformly disperse MoS2, exposing more active sites and ensuring high electronic conductivity of MoS2. In addition, the introduction of Co into MoS2 changed the intrinsic activity of MoS2 and interacted with CoSx and pyridine nitrogen in NPC, constituting a ternary catalytic interaction. Therefore, this study provides a novel strategy for optimizing the HER activity of MoS2.