An insight into improvement of room temperature formaldehyde sensitivity for graphene-based gas sensors.

• A room-temperature formaldehyde sensing material ZnO-ANS-rGO was prepared. • The facile one-pot solution synthesis avoids large energy consumption. • The dipole ANS plays a key role in decreasing working temperature of the sensor. The room temperature formaldehyde (HCHO) sensor has promising application in practical indoor air pollution detection. In this study, we assembled ZnO nanoparticles modified graphene nanosheets with dipoles by a facile solution process to fabricate a room temperature formaldehyde sensing material zinc oxide-(5-aminonaphthalene-1-sulfonic acid)-reduced graphene oxide (ZnO-ANS-rGO). The prepared ZnO-ANS-rGO sensor could detect as low as 5 ppm HCHO at room temperature. The following inverstigation showed that the outstanding gas sensing performances including high gas selectivity and reliable gas sensing reversibility were attributed to the synergism of modification of 5-aminonaphthalene-1-sulfonic acid (ANS) and ZnO nanoparticles. It was concluded that ANS greatly facilitated the charge transfer from compound to formaldehyde molecules so that the detection could be implemented at lower energy barrier. [ABSTRACT FROM AUTHOR]