Study of high-performance glycol gas sensor based on BMO/In2O3 heterostructure

Ethylene glycol (EG) is a toxic organic compound, which is harmful to human body. Hence, the advancement of gas-sensitive materials for the efficient detection of ethylene glycol (EG) holds significant practical value. This study successfully synthesized Bi₂MoO₆(BMO), In₂O₃, and BMO/In₂O₃ composite samples through the hydrothermal method. Among them, BMO/In₂O₃ composite has a spherical structure with a rough surface, has good gas sensitivity to EG, can achieve a higher response to 100 ppm EG (S = 38), and has a lower optimal operating temperature (220 °C) compared with BMO pure sample. The innovation lies in the construction of BMO/In₂O₃ heterojunction, which changes the microstructure and electron transport properties of the material, thus significantly improving the gas sensing performance. BMO/In₂O₃ sensors have good selectivity, excellent moisture resistance and long-term stability. The combination of In₂O₃ with other materials changes the microstructure of the sample, including the material particle size, optical band gap width, and vacancy oxygen ratio, and finally improves the utilization rate of the sensitive body, thus enhancing the gas-sensitive performance. The bilayer sensor has shown great application value. It can achieve super-selectivity and high-sensitivity detection of low-concentration EG at a low cost, which makes it easier to detect low-concentration EG. These results show that a BMO/In₂O₃ composite was prepared by a hydrothermal method and applied to glycol gas sensing. The composites have higher response values and lower operating temperatures compared to pure BMO. The crystal structure, micromorphology, optical and electronic properties were investigated, and the gas sensing performance and mechanism were discussed. In addition, real-time monitoring of glycol concentration was realized, demonstrating the potential of this sensor for practical applications.