Fabrication of Co3O4/PEI-GO composites for gas-sensing applications at room temperature

Abstract In this work, highly dispersed and different morphologies of Co 3 O 4 on the surface of GO modified with polyethylenimine (PEI) were synthesized by hydrothermal method at different temperatures. Co 3 O 4 /PEI-GO exhibited better gas sensing properties for NO x gas than the pure Co 3 O 4 and Co 3 O 4 /GO. Especially, the Co 3 O 4 /PEI-GO composite with hydrothermal at 190 °C for 3 h showed excellent sensitive characteristics to NO x at room temperature. The cause of good gas sensing property come mainly from the synergy between Co 3 O 4 and graphene oxide (GO) modified with PEI, which can significantly enhance the gas sensing performance. The adsorption species of NO x on the surface of Co 3 O 4 /PEI-GO composite sensor was detectable by In Situ Diffuse Reflectance Infrared Transform Spectroscopy (DRIFT). The electronic core-shell configuration model has been established to illustrate the resistance change when the Co 3 O 4 is exposed to oxidizing gases. Hence, the Co 3 O 4 /PEI-GO composite materials are promising in application of detecting NO x gas sensing.