NiS2/MoS2 Hetero-Nanosheets Grown on Double-Layered Hollow Carbon Nanospheres for Enhanced Hydrogen Evolution Reaction

To obtain catalysts with high hydrogen evolution reaction (HER) activity and low initial potential, NiS2/MoS2 composite nanosheets are grown on double-layer hollow carbon spheres (DLHCs@NiS2/MoS2) by a template method including calcination and hydrothermal processes. DLHCs as excellent electrocatalytic substrates reveal large specific surface area, high conductivity, and much more attachment sites. The DLHCs as the substrate greatly reduce the aggregation of MoS2 nanosheets, which reveal more active sites and excellent activity of hydrogen production. The result indicates that MoS2 nanosheets have high catalytic activity under acidic conditions and low catalytic activity under alkaline conditions. Furthermore, layered NiS2/MoS2 heterojunctions are created in site on DLHCs by a two-step hydrothermal procedure. The resulting sample exhibits low overpotential and high HER activity both in acidic and alkaline conditions. Using optimized preparation conditions, sample DLHCs@NiS2/MoS2-6 reveal enhanced HER activity in a broad pH range. The onset potentials are 159 and 139 mV at 1 mA cm(2) in acidic and alkaline conditions, respectively. The formation of DLHCs@NiS2/MoS2 composites provides an efficient way to develop catalysts for water splitting.