High gas-sensor and supercapacitor performance of porous Co3O4 ultrathin nanosheets

Highly porous Co3O4 ultrathin nanosheets were synthesized by a facile two-step approach, including a hydrothermal technique without any surfactant and subsequent calcination of the precursor. The as-synthesized materials belonged to the cubic spinel Co3O4 phase according to X-ray diffraction and transmission electron microscopy; and Brunauer–Emmett–Teller measurements showed that the surface area was about 97.2 m2 g−1. Owing to the unique porous ultrathin structural features, the pseudocapacitor capacitance of porous nanosheets was as high as 378 F g−1 at a current density of 1 A g−1, and the cycling stability remained about 78.5% after 2000 cycles. In addition, the porous Co3O4 ultrathin nanosheets based sensor exhibited good sensitivity and selectivity to ethanol. These results demonstrated that the porous Co3O4 ultrathin nanosheets were excellent candidates for electrochemical supercapacitor devices and ideal gas-sensor to ethanol.