Synthesis of a Flower-Like g-C3N4/ZnO Hierarchical Structure with Improved CH4 Sensing Properties

Xiaojie Li; Yanwei Li; Guang Sun; Na Luo; Bo Zhang; Zhanying Zhang

doi:10.3390/nano9050724

Synthesis of a Flower-Like g-C₃N₄/ZnO Hierarchical Structure with Improved CH₄ Sensing Properties

Nanomaterials (Basel). 2019 May 10;9(5):724. doi: 10.3390/nano9050724.

Authors

Xiaojie Li¹, Yanwei Li², Guang Sun^{3

4}, Na Luo⁵, Bo Zhang⁶, Zhanying Zhang^{7

8}

Affiliations

¹ School of Materials Science and Engineering, Cultivating Base for Key Laboratory of Environment-Friendly Inorganic Materials in University of Henan Province, Henan Polytechnic University, Jiaozuo 454000, China. lixiaojieqq101@163.com.
² School of Materials Science and Engineering, Cultivating Base for Key Laboratory of Environment-Friendly Inorganic Materials in University of Henan Province, Henan Polytechnic University, Jiaozuo 454000, China. liyanwei@hpu.edu.cn.
³ School of Materials Science and Engineering, Cultivating Base for Key Laboratory of Environment-Friendly Inorganic Materials in University of Henan Province, Henan Polytechnic University, Jiaozuo 454000, China. mcsunguang@hpu.edu.cn.
⁴ State Key Laboratory Cultivation Bases Gas Geology and Gas Control, Henan Polytechnic University, Jiaozuo 454000, China. mcsunguang@hpu.edu.cn.
⁵ School of Materials Science and Engineering, Cultivating Base for Key Laboratory of Environment-Friendly Inorganic Materials in University of Henan Province, Henan Polytechnic University, Jiaozuo 454000, China. nihaoluona@163.com.
⁶ School of Materials Science and Engineering, Cultivating Base for Key Laboratory of Environment-Friendly Inorganic Materials in University of Henan Province, Henan Polytechnic University, Jiaozuo 454000, China. zhb@hpu.edu.cn.
⁷ School of Materials Science and Engineering, Cultivating Base for Key Laboratory of Environment-Friendly Inorganic Materials in University of Henan Province, Henan Polytechnic University, Jiaozuo 454000, China. zhangzy@hpu.edu.cn.
⁸ State Key Laboratory Cultivation Bases Gas Geology and Gas Control, Henan Polytechnic University, Jiaozuo 454000, China. zhangzy@hpu.edu.cn.

Abstract

In this paper, a hierarchical structure of graphite carbon nitride (g-C₃N₄) modified ZnO (g-C₃N₄/ZnO) was synthesized using a simple precipitation-calcination method. Through this method, g-C₃N₄ nanosheets with a controlled content were successfully decorated on the petals of flower-like ZnO. Various techniques were used to confirm the successful formation of the g-C₃N₄/ZnO hierarchical structure. The methane (CH₄) sensing properties of g-C₃N₄/ZnO sensor were investigated. The result exhibited that after decorating ZnO with g-C₃N₄, the CH₄ sensing performances of the fabricated sensor were remarkably improved. At the optimum operating temperature of 320 °C, the response of the sensor fabricated with CNZ-3 (the sample with an optimum content of g-C₃N₄) towards 1000 ppm CH₄ was as high as 11.9 (R_a/R_g), which was about 2.2 times higher than that of the pure ZnO sensor (5.3). In addition, the CNZ-3 sensor also exhibited a fast response/recovery speed (15/28 s) and outstanding long-term stability. The enhancing CH₄ sensing mechanism may be contributed to enlarged surface area, pore structure, and g-C₃N₄-ZnO n-n junction.

Keywords: CH4; g-C3N4/ZnO; gas sensor; heterojunction; pores.

Grants and funding

U1704255/Zhang Zhanying