Heterostructured Co sub(3)O sub(4)/PEI-CNTs composite: fabrication, characterization and CO gas sensors at room temperature

• Published in: Journal of materials chemistry. A, Materials for energy and sustainability Vol. 2; no. 13; pp. 4558 - 4565
• Main Authors: Dang, Lifang, Zhang, Guo, Kan, Kan, Lin, Yufei, Bai, Fuquan, jing, Liqiang, Shen, Peikang, Li, Li, Shi, Keying
• Format: Journal Article
• Language: English
• Published: 01.03.2014
• DOI: 10.1039/c3ta15019d
• ISSN: 2050-7488

In this paper, a new controllable dispersion of Co sub(3)O sub(4) nanoparticles (NPs) on multiwalled carbon nanotubes (CNTs) functionalized with branched polyethylenimine (PEI) is synthesized by a noncovalent method. In Co sub(3)O sub(4)/PEI-CNTs composite, CNTs not only prevent Co sub(3)O sub(4) NPs from aggregation, but also provide an electron transfer path. The domain sizes of Co sub(3)O sub(4) NPs on Co sub(3)O sub(4)/PEI-CNTs composite synthesized with hydrothermal time 5 h at 190 degree C (named C-5) is about 4-8 nm. The surface area to volume ratio increases, the overlapped parts of Co sub(3)O sub(4) grains contain high density of defects, which provides a greater number of available active centers for gas/surface reactions. The Co sub(3)O sub(4)/PEI-CNTs composite displays excellent sensitive characteristics to CO even at a level of 5 ppm at room temperature (RT). The C-5 sensor with rapid response property and excellent stability at RT shows highly promising applications in gas sensing.