Hydrothermal Synthesis of CNTs/Co <inf>3</inf> O <inf>4</inf> @rGO Mesopours Nanocomposite as a Room Temperature Gas Sensor for VOCs

Abstract

In the present paper, the effect of reduced graphene oxide (rGO) and carbon nanotubes (CNTs) on the gas-sensing properties of Co 3 O 4 has been reported. The Co 3 O 4 /CNTs@rGO composite was synthesized using hydrothermal method. Samples were characterized by high resolution transmission electron microscope, Raman spectroscopy, Fourier transform infrared spectroscopy, differential thermal analysis, thermogravimetric analysis, Brunauer–Emmett–Teller surface area, and Barrett–Joyner–Halenda pore size measurements. The X-ray diffraction measurements confirmed the formation of the Co 3 O 4 spinel structure. The Co 3 O 4 /CNTs@rGO exhibited mesoporous structure and high specific surface area of 92.9 m 2 /g. The gas-sensing properties of the synthesized composite are evaluated toward volatile organic compounds (VOCs). The gas-sensing tests revealed that the prepared composite showed a remarkable response to ethanol at room temperature compared to other volatile organic compounds with fast response time. Due to the intriguing merits characteristics, Co 3 O 4 /CNTs@rGO composite could achieve remarkable sensitivity to VOCs especially ethanol, demonstrating great potential in next-generation room-temperature gas sensor based on P-type semiconductor.