Achieving Rich and Active Alkaline Hydrogen Evolution Heterostructures via Interface Engineering on 2D 1T-MoS2 Quantum Sheets

Large-scale production of hydrogen from water-alkali electrolyzers is impeded by the sluggish kinetics of hydrogen evolution reaction (HER) electrocatalysts. The hybridization of an acid-active HER catalyst with a cocatalyst at the nanoscale helps boost HER kinetics in alkaline media. Here, it is demonstrated that 1T-MoS2 nanosheet edges (instead of basal planes) decorated by metal hydroxides form highly active edge1T-MoS2/edgeNi(OH)2 heterostructures, which significantly enhance HER performance in alkaline media. Featured with rich edge1T-MoS2/edgeNi(OH)2 sites, the fabricated 1T-MoS2 QS/Ni(OH)(2) hybrid (quantum sized 1T-MoS2 sheets decorated with Ni(OH)(2) via interface engineering) only requires overpotentials of 57 and 112 mV to drive HER current densities of 10 and 100 mA cm(-2), respectively, and has a low Tafel slope of 30 mV dec(-1) in 1 m KOH. So far, this is the best performance for MoS2-based electrocatalysts and the 1T-MoS2 QS/Ni(OH)(2) hybrid is among the best-performing non-Pt alkaline HER electrocatalysts known. The HER process is durable for 100 h at current densities up to 500 mA cm(-2). This work not only provides an active, cost-effective, and robust alkaline HER electrocatalyst, but also demonstrates a design strategy for preparing high-performance catalysts based on edge-rich 2D quantum sheets for other catalytic reactions.