ZIF-derived porous ZnO-Co3O4 hollow polyhedrons heterostructure with highly enhanced ethanol detection performance

• Published in: Sensors and actuators. B, Chemical Vol. 253; pp. 523 - 532
• Main Authors: Xiong, Ya, Xu, Wangwang, Zhu, Zongye, Xue, Qingzhong, Lu, Wenbo, Ding, Degong, Zhu, Lei
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 01.12.2017
• Subjects: Ethanol sensor; p-n heterojunction; Porous hollow polyhedrons; ZIF-67; ZnO-decorated Co3O4; Porous hollow polyhedrons; p-n heterojunction; Ethanol sensor; ZIF-67; ZnO-decorated Co3O4
• ISSN: 0925-4005; 1873-3077
• DOI: 10.1016/j.snb.2017.06.169

Porous 2mol% ZnO-decorated Co3O4 hollow polyhedrons were synthesized by thermal decomposition of zeolitic imidazolate frameworks (ZIF-67). Experimental results reveal that this sensor presents much better ethanol sensing performance than pure Co3O4 and a low detection limit of as low as 1ppm ethanol. [Display omitted] •Porous ZnO-decorated Co3O4 hollow polyhedrons were synthesized by thermal decomposition of zeolitic imidazolate frameworks (ZIF-67) as self-sacrificial templates at 300°C.•The impacts of temperature, ZnO decoration ratio and ethanol gas concentration on the ethanol sensing performances of Co3O4 hollow polyhedrons based sensors were investigated.•The enhanced gas sensing performance of 2mol% ZnO-Co3O4 compared to that of pure Co3O4 was explained by applying p-n heterojunction theory. Porous transitional metal oxides hollow polyhedrons with controlled components have attracted tremendous attention due to their widespread applications. In this paper, novel porous ZnO-decorated Co3O4 hollow polyhedrons were synthesized by thermal decomposition of zeolitic imidazolate frameworks (ZIF-67) as self-sacrificial templates at 300°C. Experimental results reveal that the porous 2mol% ZnO-Co3O4 hollow polyhedrons present excellent response value of 106, short response/recovery time of 7/236s to 1000ppm ethanol at the optimal temperature of 200°C, much higher than that of pure Co3O4 porous hollow polyhedrons (response value of only 5.39, response/recovery time of 9/323s). Additionally, the 2mol% ZnO-Co3O4 manifests a low detection limit of 1ppm ethanol with a high response value of 1.57 and an applausive selectivity toward ethanol as compared to NH3, H2, CH4, CO2 and CH3COCH3. The enhanced gas sensing performance can be attributed to the formation of p-n heterojunction between Co3O4 and ZnO, as well as the porous hollow nanostructure with high porosity, large specific surface area, and remarkable capabilities of adsorbing oxygen. Our work offers a new avenue to employ ZIF-67 as templates for the fabrication of other hollow metal oxides with well-defined structures. More importantly, it demonstrates a great potential for the application of porous ZnO-Co3O4 hollow polyhedrons heterostructure to detect other gases.