▎ 摘　　要

Formaldehyde (HCHO) is widely known as an indoor air pollutant, and the monitoring of the gas has significant importance. However, most HCHO sensing materials do not have low detection limits and operate at high temperatures. Herein, two-dimensional (2D) mesoporous ultrathin SnO2 modified with nitrogen-doped graphene quantum dots (N-GQDs) was synthesized. The N-GQDs/SnO2 nanocomposite demonstrated high efficiency for HCHO detection. With the addition of 1.00 wt% N-GQDs, the response (R-a/R-g) of SnO2 gas sensor increased from 120 to 361 at 60 degrees C for the detection of 10 x 10(-6) HCHO. In addition, the corresponding detection limit was as low as 10 x 10(-9). Moreover, the sensor exhibited excellent selectivity and stability for the detection of HCHO. The enhanced sensing performance was attributed to both the large specific surface area of SnO2 and electron regulation of N-GQDs. Therefore, this study presents a novel HCHO sensor, and it expands the research and application potential of GQDs nanocomposites.