▎ 摘　　要

Metal oxide semiconductors (MOS)-based sensor are promising for monitoring hazardous NO2. However, the high operating temperature (e.g., 100-400 degrees C) significantly restricts practical applications. Herein a high-performance room-temperature NO2 sensor based on binary MOS and reduced graphene oxide (rGO) is demonstrated. Response of SnO2-CuO/rGO towards 50 ppm NO2 is 8-15 times higher than those of CuO/rGO and SnO2/rGO counterparts. Meanwhile, good selectivity (6 times higher response over other inorganic gases), long-term stability (decay < 5% for 7 days) and low limit of detection (150 ppb) are achieved, which can be interpreted by the p-n heterostructure and synergistic effect.