Comparative study on the H2S gas-sensing properties of graphene aerogels synthesized through hydrothermal and chemical reduction

Background: In this study, graphene aerogels (GAs) were successfully prepared through hydrothermal reduction (GA-HR) and chemical reduction (GA-CR) to determine the effect of two reduction approaches on the properties of GAs in gas-sensing applications. Methods: The GA thin films were used for the detection of H2S, and the gas-sensing performances were investigated at room temperature. S ignificant findings: The H2S gas sensitivity of GA-HR and GA-CR were 0.255 and 0.3984 ppm 1 H2S gas, respectively. GA-CR had a more compact surface morphology and slightly lower reduction degree than GA-HR. The high electrical conductivity of GA-CR, which resulted from its strong sp2 character as indicated by its ID/IG ratio (intensity ratio of D an G band in Raman spectrum), was an essential factor for its high sensitivity to H2S gas. Moreover, simulation based on density functional theory was employed to investigate the various adsorption sites for H2S gas molecules on the GAs. The theoretical calculations based on adsorption energy, charge transfer, and density of states were consistent with the experimental results indicating that the GAs had strong H2S gassensing characteristics.