Hierarchical hollow microsphere and flower-like indium oxide: Controllable synthesis and application as H2S cataluminescence sensing materials

In the present work, In 2 O 3 hierarchical hollow microsphere and flower-like microstructure were achieved controllably by a hydrothermal process in the sodium dodecyl sulfate (SDS)- N , N -dimethyl-formamide (DMF) system. XRD, SEM, HRTEM and N 2 adsorption measurements were used to characterize the as-prepared indium oxide materials and the possible mechanism for the microstructures formation was briefly discussed. The cataluminescence gas sensor based on the as-prepared In 2 O 3 was utilized to detect H 2 S concentrations in flowing air. Comparative gas sensing results revealed that the sensor based on hierarchical hollow microsphere exhibited much higher sensing sensitivity in detecting H 2 S gas than the sensor based on flower-like microstructure. The present gas sensor had a fast response time of 5   s and a recovery time of less than 25   s, furthermore, the cataluminescence intensity vs. H 2 S concentration was linear in range of 2–20   μg   mL −1 with a detection limit of 0.5   μg   mL −1 . The present highly sensitive, fast-responding, and low-cost In 2 O 3 -based gas sensor for H 2 S would have many practical applications.