Sn Doped Co3O4 Nanosheet Based Isoprene Sensor for Dynamic Metabolic Monitoring
Xiaohua Ji, Xin Wang, Qi Zhang, Siyuan Liu, Yuanyuan Lin, Zanhong Deng, Kazuki Nagashima, Yong He, Chengyin Shen, Gang MengAbstract
Sensitive and selective analysis of ppb-level breath isoprene (C5H8) by a smart chemiresistive gas sensor has attracted increasing attention for real-time metabolic monitoring. However, it remains a challenge due to its relatively weak reducibility. Herein, we report a high-performance isoprene sensor based on Sn-doped Co3O4 nanosheets. Abundant asymmetric oxygen vacancies (Co3+–OV–Sn4+) via 1 at % Sn doping, as well as preferential (400) exposed facets, noticeably improve the partial oxidation capability of isoprene at low temperature, contributing to a drastic enhancement of isoprene response. The present sensor exhibits a tiny response to diverse interference gas molecules in breath (acetone, ethanol, CO, etc.), an exceptional isoprene response (Rg/Ra = 115.2 to 10 ppm) at a low operation temperature of 100 °C, and an ultralow detection limit (LoD) of 0.13 ppb. Quantitative tracking of ppb-level breath isoprene variations during exercise could be achieved, as verified by the high linear correlation (R2 > 0.98) with proton transfer reaction-mass spectrometry (PTR‑MS) analysis, highlighting its potential for noninvasive metabolic monitoring.