NiWO4 Microflowers on Multi-Walled Carbon Nanotubes for High-Performance NH3 Detection

Min Yang; Christian Au; Guowei Deng; Shaurya Mathur; Qiuping Huang; Xiaolan Luo; Guangzhong Xie; Huiling Tai; Yadong Jiang; Chunxu Chen; Zheng Cui; Xiaoyang Liu; Chaozheng He; Yuanjie Su; Jun Chen

doi:10.1021/acsami.1c10805

NiWO₄ Microflowers on Multi-Walled Carbon Nanotubes for High-Performance NH₃ Detection

ACS Appl Mater Interfaces. 2021 Nov 10;13(44):52850-52860. doi: 10.1021/acsami.1c10805. Epub 2021 Oct 29.

Authors

Min Yang^{1

2}, Christian Au³, Guowei Deng¹, Shaurya Mathur³, Qiuping Huang¹, Xiaolan Luo¹, Guangzhong Xie², Huiling Tai², Yadong Jiang², Chunxu Chen², Zheng Cui⁴, Xiaoyang Liu⁵, Chaozheng He⁶, Yuanjie Su², Jun Chen³

Affiliations

¹ College of Chemistry and Life Science, Sichuan Provincial Key Laboratory for Structural Optimization and Application of Functional Molecules, Chengdu Normal University, Chengdu 611130, China.
² State Key Laboratory of Electronic Thin Films and Integrated Devices, School of Optoelectronic Science and Engineering, University of Electronic Science and Technology of China, Chengdu 610054, China.
³ Department of Bioengineering, University of California, Los Angeles, Los Angeles, California 90095, United States.
⁴ State Key Lab of Superhard Materials, College of Physics, Jilin University, Changchun 130012, China.
⁵ State Key Laboratory of Inorganic Synthesis and Preparative Chemistry, College of Chemistry, Jilin University, Changchun 130012, China.
⁶ Institute of Environmental and Energy Catalysis, School of Materials Science and Chemical Engineering, Xi'an Technological University, Xi'an 710021, China.

PMID: 34714039
DOI: 10.1021/acsami.1c10805

Abstract

NiWO₄ microflowers with a large surface area up to 79.77 m²·g^-1 are synthesized in situ via a facile coprecipitation method. The NiWO₄ microflowers are further decorated with multi-walled carbon nanotubes (MWCNTs) and assembled to form composites for NH₃ detection. The as-fabricated composite exhibits an excellent NH₃ sensing response/recovery time (53 s/177 s) at a temperature of 460 °C, which is a 10-fold enhancement compared to that of pristine NiWO₄. It also demonstrates a low detection limit of 50 ppm; the improved sensing performance is attributed to the porous structure of the material, the large specific surface area, and the p-n heterojunction formed between the MWNTs and NiWO₄. The gas sensitivity of the sensor based on daisy-like NiWO₄/MWCNTs shows that the sensor based on 10 mol % (MWN10) has the best gas sensitivity, with a sensitivity of 13.07 to 50 ppm NH₃ at room temperature and a detection lower limit of 20 ppm. NH₃, CO₂, NO₂, SO₂, CO, and CH₄ are used as typical target gases to construct the NiWO₄/MWCNTs gas-sensitive material and study the research method combining density functional theory calculations and experiments. By calculating the morphology and structure of the gas-sensitive material NiWO₄(110), the MWCNT load samples, the vacancy defects, and the influence law and internal mechanism of gas sensitivity were described.

Keywords: MWCNTs; NH3 sensor; flower NiWO4; heterojunction; high sensitivity.