Polyethylene imine functionalized porous carbon framework for selective nitrogen dioxide sensing with smartphone communication

Highly selective and remotely communicable nitrogen dioxide (NO2) sensing may contribute to future Internet of Things in environmental monitoring. However, room-temperature NO2 sensing materials such as carbon materials is still less than satisfactory due to their insensitive interaction with target gas. Here, polyethylene imine functionalized three-dimensional (3D) carbon framework (PEI/C framework) has been developed for enhanced selective NO2 sensing, via combined template synthesis and subsequent doping. Typically, the 3D PEI/C framework is observed porous shape with irregular coating. Beneficially, the response of C framework to NO2 increases while those of interfering gases decrease after being functionalized with PEI. Remarkably, the sensor prototypes show a 100 ppb-concentration detection limit at room temperature. Theoretically, such excellent NO2 sensing is attributed to the large specific surface ratio of porous 3D PEI/C framework, in which PEI serves as an active layer for target NO2, while a passivated one for interfering gases. Practically, such PEI/C framework sensor prototype is simulated for NO2 sensing device and communicated with a smartphone, showing great potential in future intelligent environmental monitoring.