an0c00127_si_001.pdf (3.89 MB)
1T-Phase Titanium Disulfide Nanosheets for Sensing H2S and O2
journal contribution
posted on 2020-03-26, 15:37 authored by Neha Sakhuja, Ravindra Kumar Jha, Rajneesh Chaurasiya, Ambesh Dixit, Navakanta BhatA chemiresistive,
1T-TiS2 nanosheet (TNS) based gas
sensor has been developed, and its ultrahigh sensitivity toward hydrogen
sulfide (H2S) and oxygen (O2) gas at room temperature
has been experimentally demonstrated. The sensor displayed room-temperature
detection with a maximum response of 395% to 4 ppm H2S
(reducing gas) in dry air and a response of 234% to 100% oxygen (oxidizing
gas) in ambient conditions. The H2S and O2 sensing
in humid environment (40% and 80%) has also been demonstrated so as
to ensure the reliable operation of sensor in real-time applications.
The ultrasensitive nature and linear behavior of the sensor enable
it to operate reliably in the wide range of 300 ppb to 4 ppm H2S and 1% to 100% oxygen. Density functional theory (DFT) simulations
were carried out to study the structural and electronic properties
of TNS. Adsorption behavior of these gas molecules on TNS nanosheets
was also studied theoretically. A plausible sensing mechanism based
on the theoretical model has been detailed, and interestingly, it
suggests physisorption phenomena between the adsorbate and adsorbent
which enables fast recovery of the sensor without any external stimulation.
The rather low lower limit of detection (LLoD) for H2S
and O2 reported here, specifically at room temperature,
is unique and competes favorably with reported studies. This outstanding
sensor performance can be attributed to small adsorption energy and
van der Waals interaction between analyte and the receptor.