The influence of oxygen functional groups on gas-sensing properties of reduced graphene oxide (rGO) at room temperature

Three methods were used to prepare reduced graphene oxide (rGO) with various ratios of oxygen functional groups, such as -OOH, -OH and C=O, to study their effects on the NO2 sensing properties at room temperature. It was found that the percentages of oxygen-containing species such as -OH in the rGO nanosheet, significantly affected the sensitivity of rGO to NO2 at room temperature. The -OH species can promote the sensitivity and also the recovery ability with respect to NO2. This may be because -OH has a greater attraction to NO2 and obtains electrons from it, whereas the separation of NO2 from -OH is also slightly easier, enabling a better recovery compared to other oxygen functional groups such as -OOH and C=O.