Construction of hierarchical In₂O₃/In₂S₃ microsphere heterostructures for TEA detection

Highlights

• Hierarchical In₂O₃/In₂S₃ microsphere heterostructures were constructed via incomplete oxidation of In₂S₃ precursors.

• The composition and structure of In₂O₃/In₂S₃ can be tuned by controlling the calcination temperature of the In₂S₃ precursors.

• The In₂O₃/In₂S₃ sensor exhibited high response, short response time and low detection limit towards triethylamine.

• The triethylamine sensing mechanism of In₂O₃/In₂S₃ was discussed in detail.

Abstract

Construction of heterojunction has been considered as an efficient strategy to enhance the gas-sensing performances of metal oxide semiconductors. On this basis, hierarchical In₂O₃/In₂S₃ microsphere heterostructures were synthesized by partial oxidation of In₂S₃ precursors which were obtained via a facile hydrothermal method. Besides, gas sensors based on the acquired materials were fabricated to investigate their sensing performances toward triethylamine (TEA). The results reveal that the gas sensor based on In₂O₃/In₂S₃ exhibits a high response of 37 at 300 °C toward 0.45 mg/L TEA, which is 3.7 times higher than that of bare In₂O₃. Meanwhile, it also possesses fast response/recovery time (19 s/154 s), good repeatability, selectivity and long-term stability. The excellent sensing performances toward TEA are mainly attributed to the massive oxygen vacancy defects and heterojunction formed between In₂O₃ and In₂S₃. This work provides a facile temperature-dependent route to controllably synthesize hierarchical In₂O₃/In₂S₃ microsphere heterostructures, and the In₂O₃/In₂S₃ sensor shows great application prospects in TEA detection.