N-doped three-dimensional needle-like CoS2 bridge connection Co3O4 core–shell structure as high-efficiency room temperature NO2 gas sensor

The N-doped three-dimensional (3D) needle bridge connection core-shell structure N-CoS2@Co3O4 synthesized in this work was prepared by simple hydrothermal and high-temperature vulcanization methods. The optimized N-CoS2@Co3O4-2 composite response to NO2 is 62.3–100 ppm, a response time of 1.3 s, the recovery time of 17.98 s, the detection limit of 5 ppb and stability of as long as 10 weeks at room temperature (RT). Its excellent NO2 sensing performance is attributed to the unique porous and bridge connection core-shell structure of the N-CoS2@Co3O4-2 with high specific surface area, interconnected internal channels, abundant exposed S edge active sites, and high catalytic performance promoted by N-doping. This simple manufacturing method of high-performance sensing materials paves the way for the design of N-doped bridge connection core–shell structures.