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

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 m(2) g(-1) specific surface area. The mesoporous In2O3 nanocrystals were interconnected In2O3 small grains (similar to 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 NOx 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.