Modulating the electronic structures of layer-expanded MoS2 nanoreactor via cobalt doping and carbon intercalation for enhanced electrocatalytic hydrogen evolution

Modulating the electronic structures can activate the inert basal planes of molybdenum disulfide (MoS2) leading to promoted electrocatalytic process. Here, we report the manipulation of the electronic structures of layerexpanded MoS2 nanoreactor via cobalt doping and carbon intercalation for efficient hydrogen evolution reaction (HER). Specifically, the inert basal planes are activated through cobalt doping in the MoS2, while the interlayered distance is regulated from 0.658 to 0.985 nm by introducing the carbon intercalation. The optimized Co@MoS2/C with a layer spacing of 0.920 nm presents a low overpotential of 70 mV at 10 mA cm(-2) and a Tafel slope of 50 mV dec(-1) in 0.5 M H2SO4, which is much better than most reported MoS2-based electrocatalysts. Moreover, the Co@MoS2/C also exhibits superior stability during 72 h, confirmed by the operando Raman and XRD. DFT results reveal that the electronic structures including charge density and density of states can be modulated, resulting in effortless HER. Our work opens up a new window to fabricate efficient electrocatalysts by optimizing the electronic structures.