Citation: Mishra, R.K.; Kumar, V.;
Trung, L.G.; Choi, G.J.; Ryu, J.W.;
Mane, S.M.; Shin, J.C.; Kumar, P.; Lee,
S.H.; Gwag, J.S. WS
2
Nanorod as a
Remarkable Acetone Sensor for
Monitoring Work/Public Places.
Sensors 2022, 22, 8609. https://
doi.org/10.3390/s22228609
Academic Editor: Manuel
Aleixandre
Received: 16 October 2022
Accepted: 4 November 2022
Published: 8 November 2022
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Article
WS
2
Nanorod as a Remarkable Acetone Sensor for Monitoring
Work/Public Places
Rajneesh Kumar Mishra
1
, Vipin Kumar
1
, Le Gia Trung
1
, Gyu Jin Choi
1
, Jeong Won Ryu
1
, Sagar M. Mane
2
,
Jae Cheol Shin
2,
*, Pushpendra Kumar
3
, Seung Hee Lee
4,5
and Jin Seog Gwag
1,
*
1
Department of Physics, Yeungnam University, Gyeongsan 38541, Korea
2
Division of Electronics and Electrical Engineering, Seoul Campus, Dongguk University, Seoul 04620, Korea
3
Department of Physics, Manipal University Jaipur, Jaipur 303007, India
4
Department of Nanoconvergence Engineering, Jeonbuk National University, Jeonju 54896, Korea
5
Department of Polymer Nano-Science and Technology, Jeonbuk National University, Jeonju 54896, Korea
* Correspondence: jcshin@dgu.ac.kr (J.C.S.); sweat3000@ynu.ac.kr (J.S.G.)
Abstract:
Here, we report the synthesis of the WS
2
nanorods (NRs) using an eco-friendly and facile
hydrothermal method for an acetone-sensing application. This study explores the acetone gas-
sensing characteristics of the WS
2
nanorod sensor for 5, 10, and 15 ppm concentrations at 25
◦
C, 50
◦
C,
75
◦
C, and 100
◦
C. The WS
2
nanorod sensor shows the highest sensitivity of 94.5% at 100
◦
C for the
15 ppm acetone concentration. The WS
2
nanorod sensor also reveals the outstanding selectivity of
acetone compared to other gases, such as ammonia, ethanol, acetaldehyde, methanol, and xylene
at 100
◦
C with a 15 ppm concentration. The estimated selectivity coefficient indicates that the
selectivity of the WS
2
nanorod acetone sensor is 7.1, 4.5, 3.7, 2.9, and 2.0 times higher than xylene,
acetaldehyde, ammonia, methanol, and ethanol, respectively. In addition, the WS
2
nanorod sensor
also divulges remarkable stability of 98.5% during the 20 days of study. Therefore, it is concluded that
the WS
2
nanorod can be an excellent nanomaterial for developing acetone sensors for monitoring
work/public places.
Keywords:
WS
2
nanorods; gas sensors; acetone sensing; selective nature; durability; acetone sensing
mechanism
1. Introduction
The rapidly increasing industrial evolutions in the fields of agriculture, automobiles,
biomedical, and food packaging have introduced significant concerns about environmental
monitoring technologies, leading to the development of reliable and durable gas sen-
sors [
1
]. The human exhaled breath contains numerous types of gases, such as ketones,
nitric oxide, aldehydes, volatile organic compounds, acids, and hydrogen sulfide [
2
,
3
].
Therefore, exhaled human breath is a significant and rousing issue from the outlook of
biomedical applications to inspect different diseases. Interestingly, the exhaled human
breath contains nearly 870 volatile organic compound types, indicating exclusive evidence
regarding metabolic disorders [
4
]. Therefore, studying exhaled human breath can provide
insights into crucial results of humans’ normal or abnormal metabolic states arising from
psychological stress [
5
]. Acetone molecules have been considered hazardous to human
health and the environment. Acetone is a member of a family of volatile organic com-
pounds that can influence the human nervous system and other organs under excessive
exposure to concentrations of nearly 173 ppm [
6
]. Acetone is a vital aspect of the human
metabolic system and can be examined through blood, breath, and urine [
7
,
8
]. It has been
found to be a precise biomarker to recognize individuals with diabetes type-I due to the
presence of high acetone vapor in the exhaled breath compared to healthy humans [
9
].
Various sensors, such as electrochemical, colorimetric, and resistive chemical gas, have
been studied to detect acetone [
10
–
12
]. The colorimetric sensor provides low accuracy and
Sensors 2022, 22, 8609. https://doi.org/10.3390/s22228609 https://www.mdpi.com/journal/sensors
