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 CO, 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 CO.