Robust Hydrogen-Evolving Electrocatalyst from Heterogeneous Molybdenum Disulfide-Based Catalyst

Molybdenum disulfide-based layered materials are promising electrocatalysts for hydrogen production from water electrolysis if their catalytic performance can be further improved by increasing the electrical conductivity and edge site density, and decreasing the contact resistance between the catalyst and its support. A suitable conductive scaffold can play a positive role in enhancing the relevant hydrogen evolution performance. Here we demonstrate that three-dimensional NiCoSe2 nanosheet arrays supported on Ni foam are effective as the conductive scaffold for enhancing the catalytic activity of layered MoS1.5Se0.5 particles. The resulting hierarchical MoS1.5Se0.5/NiCoSe2 hybrid electrocatalyst is highly efficient for hydrogen evolution in acid, yielding geometric current densities of 10, 50, and 100 mA cm–2 at overpotentials as low as 57, 88, and 102 mV with good long-term durability at current densities up to 500 mA cm–2 over 25 h. To the best of our knowledge, no MoS2-based electrocatalyst can realize both low overpotential affording a current density of 500 mA cm–2 and good durability at a large current density (500 mA cm–2) except this report. In particular, the double-layer capacitance, turnover frequency measurements, and high normalized exchange current density indicate its possibly high intrinsic activity for hydrogen evolution in acid. It is among the most efficient earth-abundant catalysts exhibiting a low overpotential and simultaneous good intrinsic activity reported on a three-dimensional architecture thus far.