A heterojunction composite of Bi2Se3 nanosheets and MoO3 nanobelts for a high-performance triethylamine sensor

Abstract

The combination of metal oxides and 2D nanomaterials demonstrated remarkable enhancement in gas sensing performance. In this work, a heterojunction composite of 2D Bi₂Se₃ nanosheets and 1D MoO₃ nanobelts was first synthesized by a simple and low-cost strategy. Significantly, the Bi₂Se₃/MoO₃-2 composite with a mass ratio of 2 : 1 for MoO₃ to Bi₂Se₃ exhibited a pronounced response of 151 to 10 ppm TEA at 240 °C, which was five times higher than that of MoO₃. Moreover, the sensor showed excellent selectivity to triethylamine (TEA), long-term stability (96% response retention after 30 days), and a low detection limit of ∼5.5 ppb. The enhanced TEA sensing performance can be attributed to the formation of the n–n heterojunction between Bi₂Se₃ and MoO₃, which provides more active sites for the reaction of TEA molecules and improves the electron carrier transfer from Bi₂Se₃ to MoO₃. This work demonstrates the potential of the Bi₂Se₃ nanosheet and MoO₃ nanobelt composite as an ultrasensitive sensor for TEA detection.