Synergistically Configuring Intrinsic Activity and Fin-Tube-Like Architecture of Mn-Doped MoS₂-Based Catalyst for Improved Hydrogen Evolution Reaction

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Hydrogen generation by electrocatalysis water splitting is considered as one of the most promising techniques to address the energy crisis and environmental pollution. Highly efficient, low-cost, and stable catalysts are crucial to speed sluggish kinetics of the hydrogen evolution reaction (HER). Molybdenum disulfide has been considered to be a promising substitute to Pt-based materials, but its inherently low conductivity, finite active edge sites due to the thermodynamically stable basal plane, and the self-stacking and agglomeration properties still impede the HER activity. In addition, optimization of the electrode structure is equally critical for industrial high-rate hydrogen production. Herein, on the basis of the system engineering concept, we report a manganese-doped MoS 2 ultrathin nanosheet anchoring on a fin-tube-like hierarchical carbon skeleton vertically to achieve the synergistic optimization of intrinsic activity and electrode architecture. The superhydrophilic and superaerophobic electrode with conductive carbon nanoarray structure can accelerate the mass transport (gas bubbles and electrolyte) and electron transfer processes. In addition, theoretical calculation reveals that all the hydrogen adsorption free energies of basal planes, S-edge, and Mo-edge for doped MoS 2 have decreased. Moreover, the electronic structure of the Mn-doped MoS 2 monolayer shows the absence of band gap, indicating improved inherent conductivity. This finely crafted self-supported binder-free electrode with integrated architecture shows a low overpotential of 130 mV at −10 mA/cm 2, a Tafel slope as low as 44 mV/dec, and excellent durability even at a high cathodic current density of 200 mA/cm 2 in 0.5 M H 2 SO 4 . This system engineering optimizing strategy may pave the way for the design of commercially available electrocatalysts.