Mesoporous In2O3 nanocrystals: synthesis, characterization and NOx gas sensor at room temperature

Abstract

Mesoporous In₂O₃ nanocrystals (INS) were successfully prepared using SBA-16 as the template. The sample INS-3, synthesized from a 0.3 M In(NO₃)₃ solution, had a 7.27 nm mean pore size and 82.32 m² g⁻¹ specific surface area. The mesoporous In₂O₃ nanocrystals were interconnected In₂O₃ small grains (∼5 nm) with a pore wall thickness of about 5–10 nm, and the natural pores provided effective gas adsorption–desorption and fast transportation of carriers, resulting in better diffusivity of the analyte gases. Therefore, the INS-3 sensor exhibited sensing properties with a high response of 158.7 and a low detection limit of 970 ppb to 97 ppm NO_x at room temperature (RT), which can be attributed to the synergistic effect between its unique mesoporous and well-crystalline structure. The INS-3 sensor has significant applications for gas sensing.