Graphdiyne: a Highly Sensitive Material for ppb-Level NO2 Gas Sensing at Room Temperature

Detection of a trace amount of NO2 at room temperature has very important applications in air quality monitoring, protection of human health and medical diagnose. However, the existing NO2 sensors often suffer from low sensitivity when the concentration at the ppb-level. Here, we report a new kind of materials based on graphdiyne(GDY) for highly sensitive detection of ppb-level(ppb: part per billion) NO2 at room temperature. After thermal treatment of the as-prepared GDY at 600 °C under argon atmosphere for 2 h(the obtained sample denoted as GDY-600), the prepared sensor with GDY-600 displays excellent sensitivity with a response value of 6.2% towards 250 ppb NO2 at room temperature, which is better than most of reported sensing materials. In addition, the sensor exhibits significantly high selectivity to NO2 against typical interfering gases including CO, CO2, NH3, H2, H2S and toluene. Moreover, the sensor shows remarkable stability after repetitive measurements. The superior sensing performance of GDY-600 can be ascribed to the highly π-conjugated structure with special acetylenic bonds and abundant oxygen-containing functional groups, which are all beneficial for the gas adsorption and redox reaction on the surface.