Ma, X., Zhu, H., Yu, L., Li, X., Ye, E., Li, Z., Loh, X. J., & Wang, S. (2023). Rare-earth-doped indium oxide nanosphere-based gas sensor for highly sensitive formaldehyde detection at a low temperature. Nanoscale, 15(4), 1609–1618. https://doi.org/10.1039/d2nr04972d
Abstract:
Formaldehyde (HCHO) is widely viewed as a carcinogenic volatile organic compound (VOC) in indoor air pollution, which can bring serious threaten to people’s life. Thus, it is very crucial to develop gas sensors with improved sensing performance like outstanding selectivity, low operating temperature, high responsiveness, and short recovery time for HCHO detection. Currently, doping is found to be one effective strategy to raise the sensing performance of a gas sensor. Herein, various rare earth elements doped indium oxide (RE-In2O3) nanospheres were fabricated as a gas sensor for improved HCHO detection via a facile and environmentally friendly solvothermal method. Such RE-In2O3 nanospheres based sensors exhibited remarkable gas sensing performance including high selectivity and stability in air at RT. In particular, comparing with pure, Yb, Dy doped In2O3 and differrnt La ratios doped into In2O3, 6% La doped In2O3 (La-In2O3) nanospheres based sensors were demonstrated a high response value of 210 to 100 ppm at 170 °C, which was around 16 times higher than that of pure In2O3 sensor, and also exhibited a detection limit of 10.9 ppb, a response time of 30 s to 100 ppm HCHO with a recovery time of 160 s. In the end, such superior sensing performance of 6% La-In2O3 sensors was proposed to be attributed to the synergistic effect of large specific surface area and enhanced surface oxygen vacancies on the surface of In2O3 nanospheres, which produced chemisorbed oxygen species to release electrons and provided abundant reaction sites for HCHO gas. This study sheds new light on designing nanomaterial to build gas sensors for HCHO detection.
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Funding Info:
This work was supported by the National Natural Science Foundation of China (U21A20290, 82001957), the Guangdong Basic and Applied Basic Research Foundation (2022A1515011656)