Ppb-Level Xylene Gas Sensors Based on Co3O4 Nanoparticle-Coated Reduced Graphene Oxide(rGO) Nanosheets Operating at Low Temperature

Xylene is a toxic carcinogen, which may irritate eyes and respiratory tract, or damage the central nervous system. However, the traditional semiconductor gas sensor can only detect the ppm level of xylene gas, which cannot meet the building air quality monitoring requirements. Therefore, the development of low concentration gas detection of xylene gas sensor is necessary. In this article, a one-step hydrothermal method for the preparation of reduced graphene oxide (rGO)/Co3O4 nanocomposite was reported. Then, rGO/Co3O4 nanocomposites were characterized by various characterization methods. It was found that the structure of cobalt tetroxide (Co3O4) nanoparticle-coated rGO nanosheets was successfully synthesized. Specific internal morphology could be seen by scanning electron microscopy (SEM) and transmission electron microscopy (TEM). Then the gas sensor made of rGO/Co3O4 nanocomposite material was tested for its gas sensitivity performance. A series of properties such as repeatability and stability of the material were tested. According to the test results, the sensitivity of 1rGO/Co3O4 (335 wt%) to xylene gas was better than that of 2rGO/Co3O4 (5.54 wt%) and pure Co3O4, and the optimal working temperature of rGO/Co 3 0 4 to 50 ppm xylene was 175 degrees C, which was 50 degrees C lower than that of pure Co3O4. In addition, the rCO/Co3O4 gas sensor could also detect xylene gas with a minimum concentration of 1 pph. Finally, the gas sensing mechanism of the gas sensor for xylene gas was analyzed.

Automated summary

This article presents a one-step hydrothermal method for the preparation of rGO/Co3O4 nanocomposites and their performance testing. The results show that 1rGO/Co3O4 (335 wt%) has the best sensitivity to xylene gas, with an optimal working temperature of 175 degrees Celsius, and can detect xylene gas with a minimum concentration of 1 pph.