Ag/Cu Bimetallic Nanoparticles Loaded on In2O3 for Rapid and Ultrasensitive Room-Temperature NO2 Detection

Breakthrough: Ag/Cu bimetallic sensitization and UV activation enables efficient room-temp NO 2 detection. • High response (2180 to 200 ppm NO 2 ) with fast 7/10   s response/recovery at RT under UV. • High selectivity and moisture resistance, integrated into smart masks for breath-level detection. Metal oxide semiconductor (MOS) NO 2 gas sensors are hindered from achieving high-performance, low-power practical applications due to their slow response/recovery times and excessively high operating temperatures. To overcome these obstacles, we propose a synergistic strategy combining silver/copper (Ag/Cu) bimetallic nanoparticle surface modification with ultraviolet (UV) light activation. Using NH 2 -MIL-68 as a sacrificial template, In 2 O 3 rod-like materials were prepared via a hydrothermal method, and Ag/Cu bimetallic nanoparticles were further decorated on their surface to construct a high-performance NO 2 sensor (Ag/Cu-In 2 O 3 ) capable of operating at room temperature. Under UV light excitation, the Ag/Cu-In 2 O 3 -1 sensor exhibited a high response of 2180 toward 200 ppm NO 2 , with response and recovery times as short as 7   s and 10   s, respectively. Moreover, the sensor showed excellent selectivity for NO 2 against various interfering gases and good humidity tolerance. The enhanced performance is attributed to the synergistic sensitization of Ag/Cu bimetallic nanoparticles and the photogenerated holes induced by UV illumination during response and recovery. This study highlights the potential of Ag/Cu-In 2 O 3 for room-temperature NO 2 sensing and demonstrates the effectiveness of UV excitation in boosting MOS gas sensor performance. Download: Download high-res image (135KB) Download: Download full-size image