Oxygen-Incorporated MoS2 Nanosheets with Expanded Interlayers for Hydrogen Evolution Reaction and Pseudocapacitor Applications.

Two-dimensional transition-metal dichalcogenides (TMDs) nanosheets have attracted tremendous research interest. Engineering the structure of MoS2 may result in desirable performance for energy applications. In this work, oxygen-incorporated MoS2 nanosheets with expanded interlayers have been synthesized by a solvothermal reaction. The oxygen-incorporated MoS2 nanosheets with rich defects demonstrate excellent hydrogen evolution reaction activity with a small Tafel slope of 42 mV decade-1 as well as excellent long-term stability. Interestingly, a large expanded ∼8.40 Å interlayer of (002) faces can be achieved by controlling the reaction time. This material also shows excellent long-term cycling stability (up to 20 000 cycles) as well as high specific capacitance for pseudocapacitors. We believe that the structural modification strategy can be applied for other TMDs to further optimize the performance for various applications.