Lattice expansion and oxygen vacancy of α-Fe2O3 during gas sensing

Zhengmao Cao; Zhongwei Jiang; Liping Cao; Yao Wang; Changhao Feng; Chengzhi Huang; Yuanfang Li

doi:10.1016/j.talanta.2020.121616

Lattice expansion and oxygen vacancy of α-Fe₂O₃ during gas sensing

Talanta. 2021 Jan 1:221:121616. doi: 10.1016/j.talanta.2020.121616. Epub 2020 Sep 2.

Authors

Zhengmao Cao¹, Zhongwei Jiang¹, Liping Cao¹, Yao Wang², Changhao Feng¹, Chengzhi Huang³, Yuanfang Li⁴

Affiliations

¹ Key Laboratory of Luminescence Analysis and Molecular Sensing (Southwest University), Ministry of Education, College of Chemistry and Chemical Engineering, Southwest University, Chongqing, 400715, PR China.
² Key Laboratory of Luminescent and Real-Time Analytical System (Southwest University), Chongqing Science and Technology Bureau, College of Pharmaceutical Science, Southwest University, Chongqing, 400715, PR China.
³ Key Laboratory of Luminescent and Real-Time Analytical System (Southwest University), Chongqing Science and Technology Bureau, College of Pharmaceutical Science, Southwest University, Chongqing, 400715, PR China. Electronic address: chengzhi@swu.edu.cn.
⁴ Key Laboratory of Luminescence Analysis and Molecular Sensing (Southwest University), Ministry of Education, College of Chemistry and Chemical Engineering, Southwest University, Chongqing, 400715, PR China. Electronic address: liyf@swu.edu.cn.

PMID: 33076146
DOI: 10.1016/j.talanta.2020.121616

Abstract

Identifying the nature of gas-sensing material under the real-time operating condition is very critical for the research and development of gas sensors. In this work, we implement in situ Raman and XRD to investigate the gas-sensing nature of α-Fe₂O₃ sensing material, which derived from Fe-based metal-organic gel (MOG). The active mode of α-Fe₂O₃ as gas-sensing material originate from the thermally induced lattice expansion and the changes of surface oxygen vacancy of α-Fe₂O₃ could be reflected from the further monitored Raman scattering signals during acetone gas sensing. Meanwhile, the prepared α-Fe₂O₃ gas sensor exhibits excellent gas-sensing performance with high response value (R_a/R_g = 27), rapid response/recovery time (1 s/80 s) for 100 ppm acetone gas, and broad response range (5 - 900 ppm) at 183 °C. Strategies described herein could provide a promising approach to obtain gas-sensing materials with excellent performance and unveil the gas-sensing nature for other metal-oxide-based chemiresistors.

Keywords: Gas sensing; In situ Raman spectroscopy; Lattice expansion; Oxygen vacancy; α-Fe(2)O(3).