Specific synthesis of CoS2 nanoparticles embedded in porous Al2O3 nanosheets for efficient hydrogen evolution and enhanced lithium storage

CoS2 nanoparticles embedded in Al2O3 nanosheets (CoS2 NP/Al2O3 NSs) have been designed and fabricated using a controllable hydrothermal process followed by a simple low-temperature sulfurization step. The as-prepared CoS2 NP/Al2O3 NSs display combined properties of high nanoporosity, thin thickness and good structural stability. When used as an electrocatalyst for the hydrogen evolution reaction (HER), the composite demonstrates high catalytic activity, including a small overpotential of ∼53 mV, a small Tafel slope of 50.9 mV dec−1 and remarkable stability. Moreover, the CoS2 NP/Al2O3 NSs have a promising lithium-storage capability with high specific capacity (∼1150 mA h g−1 at 100 mA g−1 in the first cycle) and enhanced cycling stability (coulombic efficiency of around 96% for 150 cycles). The facile strategy used to synthesize the unique architecture could be expanded to the preparation of other transition metal sulfides for the HER and lithium ion batteries (LIBs).