Ag-nanoparticles-anchored mesoporous In2O3 nanowires for ultrahigh sensitive formaldehyde gas sensors

As the core component of gas sensors, the sensing mediums with excellent gas-sensing performance are strongly required. Herein, Ag nanoparticles were implanted into mesoporous indium oxide nanowires (In2O3 NWs) to form Ag-loaded In2O3 NW. All results indicated that Ag nanoparticles are well-dispersed in mesopores of In2O3 NWs and significantly affect specific surface area and interface oxygen vacancies. Moreover, Ag-loading tremendously improves the formaldehyde (HCHO) gas-sensing performance of Ag-loaded In2O3 sensors. Owing to Ag catalysis, the operating temperature decreases from 210 ℃ for In2O3 sensor to 150 ℃ for Ag-loaded In2O3 sensor. Ag0.025-In2O3 sensor exhibits the highest response (877.3) to 10 ppm HCHO for more oxygen vacancies and Ag spillover effect, which is about 33 times of In2O3 sensor. The formation of Schottky heterojunctions at the interface between Ag and In2O3 leads to the electron transition from In2O3 to Ag, which increases the resistance in air and HCHO gas for Ag-loaded In2O3 sensors.