ZnO Nanorods Grown on WS2Nanosheets for Chemiresistive H2S Sensing

Sakhuja, N and Jha, RK and Sai, R and Bhat, N (2022) ZnO Nanorods Grown on WS2Nanosheets for Chemiresistive H2S Sensing. In: ACS Applied Nano Materials, 5 (7). pp. 9241-9251.

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Abstract

A scalable and CMOS-compatible fabrication of a transition-metal dichalcogenide-oxide heterostructure based chemiresistive sensor for the selective detection of hydrogen sulfide (H2S) gas is detailed here. WS2 nanosheets, obtained by a liquid exfoliation technique, were used as the seed 2D material for fabricating the nano heterostructures. Using a microwave-irradiation-assisted solvothermal (MAS) process, ZnO nanorods (1D) were grown in situ on these 2D nanosheets, resulting in a 2D/1D heterostructure. The processing in an alcohol-rich solution medium also enabled the formation of a thin 2D-like layer of metal sulfate and/or metal oxide on the surface of these 2D nanosheets, thus forming the 2D/2D heterojunction. In presence of both 2D/1D and 2D/2D heterostructures, termed together as co-HS, the active sites are augmented for H2S sensing. Furthermore, the formation of neat 1D/2D interfaces provides additional electron conduction paths while creating active sites at the basal plane of WS2, which is otherwise inert. Therefore, this unique structure aided in achieving a 5-fold selectivity (5:1) to H2S among other interfering gases such as NH3, SO2, NO2, etc. with a reasonably good response magnitude (140 to 5 ppm) in the range of 100 ppb to 5 ppm. Notably, the sensor showed a speedy response of less than 1 min and a recovery of less than 50 s at concentrations of 1 ppm and lower, with a remarkable achievement of 14 s recovery at 500 ppb. The long-term stability of the sensor for at least 6 months is also demonstrated to be promising. The sub-ppm detection enables the sensor to be employed in breath-based diagnostics.

Item Type:	Journal Article
Publication:	ACS Applied Nano Materials
Publisher:	American Chemical Society
Additional Information:	The copyright for this article belongs to the American Chemical Society.
Keywords:	Ammonia; Chemical sensors; Gas detectors; Heterojunctions; II-VI semiconductors; Microwave irradiation; Nanorods; Nanosheets; Transition metals; Tungsten compounds; Zinc oxide, 2d/1d; 2d/2d/1d; Active site; CMOS Compatible; Gas-sensors; H2S gas sensor; Nanorods grown; TMD; Transition metal dichalcogenides (TMD); ZnO nanorod, Sulfur compounds
Department/Centre:	Division of Interdisciplinary Sciences > Centre for Nano Science and Engineering
Date Deposited:	10 Aug 2022 05:57
Last Modified:	10 Aug 2022 05:57
URI:	https://eprints.iisc.ac.in/id/eprint/75789

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