Effect of solvothermal temperature on the surface chemical properties and triethylamine gas-sensing performance of In₂O₃

In₂O₃ microstructure and surface chemistry was regulated by solvothermal temperature. • 160 °C-In₂O₃-based sensor exhibited a high TEA response of 123.58 at 170 °C. • Abundant chemisorbed oxygen endowed In₂O₃ with superior TEA-sensing ability. • DFT calculations confirmed that oxygen vacancies strengthen the adsorption of TEA on In₂O₃. In this work, a series of In₂O₃ nanomaterials were synthesized via a solvothermal method at 120, 130, 160, and 190°C, and the effects of solvothermal temperature on their crystal structure, surface properties, and triethylamine (TEA) gas-sensing performance were comprehensively investigated. The results showed that the In₂O₃ sample obtained at 160°C delivered the maximum response (123.58) to 50 ppm TEA at the optimal operating temperature of 170°C, together with superior selectivity and long-term stability. Structural characterization revealed that the solvothermal temperature significantly influenced the grain size, surface morphology, and surface adsorbed oxygen content of the samples. Compared with the other samples, the 160 °C-In₂O₃ sample possessed an moderate grain size, a relatively uniform mesoporous structure, and a higher concentration of chemisorbed oxygen species, which facilitated gas diffusion and surface reaction processes. Furthermore, density functional theory (DFT) simulations indicated that oxygen vacancies could enhance the adsorption capability of TEA molecules, thereby promoting the gas-sensing reaction. These findings demonstrated that an appropriate solvothermal temperature could effectively regulate the surface structure and gas adsorption characteristics of In₂O₃, providing valuable guidance for the design of high-performance TEA gas-sensing materials. Download: Download high-res image (97KB) Download: Download full-size image