Tuning the electrical conductivity of amorphous carbon/reduced graphene oxide wrapped-Co3O4 ternary nanofibers for highly sensitive chemical sensors

Qiuxia Feng; Yamei Zeng; Pengcheng Xu; Shiwei Lin; Chao Feng; Xiaogan Li; Jing Wang

doi:10.1039/C9TA11550A

Tuning the electrical conductivity of amorphous carbon/reduced graphene oxide wrapped-Co₃O₄ ternary nanofibers for highly sensitive chemical sensors†

Qiuxia Feng,^ab Yamei Zeng,^c Pengcheng Xu,

^d Shiwei Lin,^c Chao Feng,^a Xiaogan Li

*^a and Jing Wang*^a

Author affiliations

* Corresponding authors

^a School of Microelectronics, Faculty of Electronic Information and Electrical Engineering, Key Lab. of Liaoning for Integrated Circuits Technology, Dalian University of Technology, Dalian, China
E-mail: lixg@dlut.edu.cn, wangjing@dlut.edu.cn

^b School of Intelligence & Electronic Engineering, Dalian Neusoft University of Information, Dalian, China

^c State Key Laboratory of Marine Resource Utilization in South China Sea, College of Materials and Chemical Engineering, Hainan University, Haikou 570228, PR China

^d State Key Lab of Transducer Technology, Shanghai Institute of Microsystem and Information Technology, Chinese Academy of Sciences, Shanghai, China

Abstract

The electrical conductivity of amorphous carbon/reduced graphene oxide(rGO)-wrapped Co₃O₄ nanofibers prepared by the electrospinning process is for the first time finely tuned creatively by the thermal-etching process during which the amorphous carbon is removed and the further growth of Co₃O₄ nanocrystals within amorphous carbon occurs through thermal oxidation. The influence of electrical conductivity on the room-temperature ammonia sensing properties of these ternary composite material based sensors can thus be investigated for the first time. The fabricated chemiresistive-type sensor using the ternary sample thermally oxidized at 390 °C in a controlled O₂ environment shows a good sensitivity and fast response (∼20 s: 50 ppm) to different concentrations of ammonia from 1–100 ppm at room temperature. The sensor demonstrates an excellent selectivity to several possible interferents such as methanol, ethanol, formaldehyde, methylbenzene, benzene, acetone and water and a brilliant long-term stability for about four years. Density functional theory (DFT) calculations are performed to study the coupling effect at the interface of graphene/Co₃O₄ (110B) which plays a crucial role in the sensing performance to NH₃. The underlying chemical sensing process is examined using in situ Fourier transform infrared spectroscopy (FTIR) which shows a water-mediated catalytic oxidation transducing mechanism.

This article is part of the themed collection: 2019 Journal of Materials Chemistry A HOT Papers

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Article information

DOI: https://doi.org/10.1039/C9TA11550A
Article type: Paper
Submitted: 20 Oct 2019
Accepted: 10 Nov 2019
First published: 14 Nov 2019

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J. Mater. Chem. A, 2019,7, 27522-27534

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Tuning the electrical conductivity of amorphous carbon/reduced graphene oxide wrapped-Co₃O₄ ternary nanofibers for highly sensitive chemical sensors

Q. Feng, Y. Zeng, P. Xu, S. Lin, C. Feng, X. Li and J. Wang, J. Mater. Chem. A, 2019, 7, 27522 DOI: 10.1039/C9TA11550A

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Journal of Materials Chemistry A