Plasma-assisted synthesis of 2D MoS2 nanosheets with tunable sulfur defects for highly efficient nitrogen reduction reaction

•Defect-rich 2D-MoS2 is prepared by DBD plasma.•The sulfur defects of MoS2 are conveniently regulated by plasma treatment.•The mechanism behind plasma stripping process is gas expansion and electron repulsion.•Defect-rich MoS2 nanosheet exhibits improved NRR activity.•DFT calculations reveals the role of S defects of MoS2 in NRR process.