Construction of organic-inorganic "chelate" adsorption sites on metal oxide semiconductor for room temperature NO2 sensing

Ya-Kun Lv; Xiao-Jie Li; Yan-Yang Li; Xiaobiao Liu; Hong-Chang Yao; Zhong-Jun Li

doi:10.1016/j.jhazmat.2022.128623

Construction of organic-inorganic "chelate" adsorption sites on metal oxide semiconductor for room temperature NO₂ sensing

J Hazard Mater. 2022 Jun 15:432:128623. doi: 10.1016/j.jhazmat.2022.128623. Epub 2022 Mar 3.

Authors

Ya-Kun Lv¹, Xiao-Jie Li², Yan-Yang Li³, Xiaobiao Liu⁴, Hong-Chang Yao⁵, Zhong-Jun Li¹

Affiliations

¹ Green Catalysis Center, College of Chemistry, Zhengzhou University, Zhengzhou 450001, China.
² School of Material Science and Engineering, Shanghai University, Shanghai 200444, China.
³ Green Catalysis Center, College of Chemistry, Zhengzhou University, Zhengzhou 450001, China. Electronic address: yyli@zzu.edu.cn.
⁴ School of Sciences, Henan Agricultural University, Zhengzhou 450002, China.
⁵ Green Catalysis Center, College of Chemistry, Zhengzhou University, Zhengzhou 450001, China. Electronic address: yaohongchang@zzu.edu.cn.

PMID: 35290895
DOI: 10.1016/j.jhazmat.2022.128623

Abstract

Metal oxide semiconductors (MOS) have been extensively studied for gas sensing due to their excellent chemical stability and adjustable electronic properties. However, there is still a lack of ingenious design strategies to achieve customizable gas detection in complex environments. Herein, a novel and scalable strategy of constructing organic-inorganic "chelate" adsorption sites is proposed to promote the affinity of MOS sensing materials to target molecules. Specifically, 3-aminopropyltriethoxysilane (APTES)-functionalized reduced graphene oxide (rGO) was decorated on In₂O₃ tubes (AG/In_x), and its NO₂ sensing performance was studied. As a result, the optimal AG/In_x shows boosted room-temperature NO₂ response, and its response to 1 ppm NO₂ is 4.8 times that of In₂O₃. More attractively, the optimal AG/In_x exhibits good selectivity, as well as outstanding detection ability (R_g/R_a = 1.6) for low concentration NO₂ (20 ppb). Experimental results suggest that APTES-rGO not only acts as the electron acceptor to accelerate charge transfer, but also enhances NO₂ adsorption. Further theoretical calculations reveal that NO₂ is simultaneously adsorbed at rGO and APTES via a flexible "chelate" mechanism. The multidentate adsorption configuration remarkably strengthens the NO₂-host interaction, which is conducive to improving sensing performance. This work may inspire the material design of a new generation high-performance gas sensors.

Keywords: Chelate adsorption; Heterojunction; Metal oxide semiconductors; NO(2) gas sensors; Room temperature.