High performance langasite based SAW NO 2 gas sensor using 2D g-C 3 N 4 @TiO 2 hybrid nanocomposite

• Published in: Journal of hazardous materials Vol. 427; p. 128174
• Main Authors: Pasupuleti, Kedhareswara Sairam, Reddeppa, Maddaka, Chougule, S S, Bak, Na-Hyun, Nam, Dong-Jin, Jung, Namgee, Cho, Hak Dong, Kim, Song-Gang, Kim, Moon-Deock
• Format: Journal Article
• Language: English
• Published: Netherlands 05.04.2022
• Subjects: Hybrid heterojunction; SAW; NO gas; Langasite; TiO nanoplates; g-CN

Nitrogen dioxide (NO ) gas has emerged as a severe air pollutant that causes damages to the environment, human life and global ecosystems etc. However, the currently available NO gas sensors suffers from insufficient selectivity, sensitivity and long response times that impeding their practical applicability for room temperature (RT) gas sensing. Herein, we report a high performance langasite (LGS) based surface acoustic wave (SAW) RT NO gas sensor using 2-dimensional (2D) g-C N @TiO nanoplates (NP) with {001} facets hybrid nanocomposite as a chemical interface. The g-C N @TiO NP/LGS SAW device showed a significant negative frequency shift (∆f) of ~19.8 kHz which is 2.4 fold higher than that of the pristine TiO NP/LGS SAW sensor toward 100 ppm of NO at RT. In addition, the hybrid SAW device fascinatingly exhibited a fast response/recovery time with a low detection limit, high selectivity, and an effective long term stability toward NO gas. It also exhibited an enhanced and robust negative frequency shifts under various relative humidity conditions ranging from 20% to 80% for 100 ppm of NO gas. The high performance of the g-C N @TiO NP/LGS SAW gas sensor can be attributed to the enhanced mass loading effect which was assisted by the large surface area, oxygen vacancies, OH and amine functional groups of the n-n hybrid heterojunction of g-C N @TiO NP that provide abundant active sites for the adsorption and diffusion of NO gas molecules. These results emphasize the significance of the integration of 2D materials with metal oxides for SAW based RT gas sensing technology holds great promise in environmental protection.