Oxygen vacancies and grain boundaries potential barriers modulation facilitated formaldehyde gas sensing performances for In2O3 hierarchical architectures

The distinctive In2O3 hierarchical architectures are successfully prepared via a facile solution route at room temperature combined with a subsequent thermal treatment. Microstructural characterizations by means of SEM, TEM and XRD indicate the as-prepared In2O3 hierarchical architectures are assembled by nanoparticles and show loose porous surfaces. The room temperature PL spectra and BET surface area analyses demonstrate In2O3 hierarchical architectures possess more oxygen vacancies and larger surface area. To demonstrate potential applications of such hierarchical porous architectures, as-prepared In2O3 samples are fabricated to be gas sensors to investigate their gas sensing properties. The gas sensing tests reveal In2O3 hierarchical architectures exhibit excellent formaldehyde sensing performances with rapid response/recovery behavior (1 s/8 s), good selectivity and favorable stability for 100 ppm formaldehyde (HCHO) at 260 °C. The sensitivity of In2O3 hierarchical architectures is about 4 times higher than that of In2O3 nanoparticles. The cooperative effect between oxygen vacancies and grain boundaries potential barriers induced by hierarchical porous architecture contributes to the improvement of gas sensing performances. The favorable gas sensing properties make In2O3 hierarchical architecture becomes a promising material for formaldehyde detection.