Selective ppb-level ozone gas sensor based on hierarchical branch-like In2O3 nanostructure

For realizing high-performance ozone (O 3 ) sensing, hierarchical branch-like In 2 O 3 (B-In 2 O 3 ) nanomaterials were designed and prepared via a facile co-precipitation method. The unique In 2 O 3 structure consists of abundant nano-rods with the length of ca. 450 nm enabling effective adsorption and diffusion of oxygen and O 3 molecules. The sensors based on B-In 2 O 3 showed sensitive O 3 sensing performances at a relative low working temperature. The response of B-In 2 O 3 based sensors to 100 ppb of O 3 is 44 at 70 °C, which is 4.9-fold higher than the commercial In 2 O 3 (C-In 2 O 3 ) particles. The limit of O 3 detection was as low as 30 ppb. Moreover, the gas sensor exhibited excellent selectivity and device stability. The great sensing behavior is proved to be closely related to the oxygen-chemisorbed ability and large specific surface area of In 2 O 3 materials. Taken together, this work provides a potential sensing platform for highly sensitive and ppb-level O 3 detection.