A bio-inspired and switchable H+/OH ion-channel for room temperature exhaled CO2 chemiresistive sensing

Honghao Chen, Ruofei Lu, Yixun Gao, Xiaorui Yue, Haihong Yang, Hao Li, Yi Kuen Lee, Paddy J. French, Yao Wang*, Guofu Zhou

*Corresponding author for this work

Research output: Contribution to journalArticleScientificpeer-review


Inspired by the CO2-induced reversible activation mechanism of the slow anion channel 1 (SLAC1) in plant stomatal guard cells during plant photosynthesis, we designed and prepared a CO2- switchable H+/OH ion channel (CSPH ion channel). A high-performance chemiresistive room temperature CO2 sensor has been prepared based on this CSPH ion channel. The obtained CO2 room temperature sensor γ-CD-MOF@RhB exhibits high sensitivity (Rg/R0 = 1.50, 100 ppm), excellent selectivity, good stability (less than 5% reduction in 30 days response value), and 99.96% consistency with commercial infrared CO2 meter. The practical limit of detection (pLOD) of the γ-CD-MOF@RhB sensor reaches 10 ppm at room temperature toward CO2, which is the lowest for reported MOF-derived chemiresistive room temperature CO2 sensors so far. Ion conduction mechanism studies have shown that the CSPH ion channel behaves as a CO2-switchable H+/OH ion channel with a switching point of approximately 60 000 ppm CO2. As an application attempt, the fabricated low pLOD CO2 sensor has been used for human exhaled CO2 detection to compare CO2 concentration in the breath of individuals before and after exercise and COVID-19. It was also logically indicated that the average concentration of human exhaled CO2 after COVID-19 recovery is different for undiseased subjects.

Original languageEnglish
Pages (from-to)21959-21971
Number of pages13
JournalJournal of Materials Chemistry A
Issue number40
Publication statusPublished - 2023

Bibliographical note

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This work was supported by the National Natural Science Foundation of China (Grant No. 51973070), Science and Technology Program of Guangzhou (No. 2019050001), Guangdong Basic and Applied Basic Research Foundation (2022A1515010577 and 2021A1515012420), Innovative Team Project of Education Bureau of Guangdong Province (2018KCXTD009), Guangdong Science and Technology Project-International Cooperation (2022A0505050069), Start-up Foundation from SCNU, Guangdong Provincial Key Laboratory of Optical Information Materials and Technology (No. 2017B030301007), MOE International Laboratory for Optical Information Technologies, and the 111 Project, Science and Technology Innovation Strategy Special Foundation of Guangdong (No. pdjh2023b0144). The calculations were performed at Bianshui Riverside Supercomputing Center (BRSC).


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