ABSTRACT
Significant progress has been made in two-dimensional material-based sensing devices over the past decade. Organic vapor sensors, particularly those using graphene and transition metal dichalcogenides as key components, have demonstrated excellent sensitivity. These sensors are highly active because all the atoms in the ultra-thin layers are exposed to volatile compounds. However, their selectivity needs improvement. We propose a novel gas-sensing device that addresses this challenge. It consists of two side-by-side sensors fabricated from the same active material, few-layer molybdenum disulfide (MoS2), for detecting volatile organic compounds like alcohol, acetone, and toluene. To create a dual-channel sensor, we introduce a simple step into the conventional 2D material sensor fabrication process. This step involves treating one-half of the few-layer MoS2 using ultraviolet-ozone (UV-O3) treatment. The responses of pristine few-layer MoS2 sensors to 3000 ppm of ethanol, acetone, and toluene gases are 18%, 3.5%, and 49%, respectively. The UV-O3-treated few-layer MoS2-based sensors show responses of 13.4%, 3.1%, and 6.7%, respectively. This dual-channel sensing device demonstrates a 7-fold improvement in selectivity for toluene gas against ethanol and acetone. Our work sheds light on understanding surface processes and interaction mechanisms at the interface between transition metal dichalcogenides and volatile organic compounds, leading to enhanced sensitivity and selectivity.
ABSTRACT
The synthesis and characterization of a novel covalent organic polymer cobalt (II) phthalocyanine (ATA-100) including tetra amino group is described for the first time. This covalent organic polymer (COP) is characterized by FTIR, TGA, RAMAN, PXRD, and SEM-EDS. The developed sensor is tested for acetone, ethyl butyrate, n-hexane, chloroform, and n-butyraldehyde in a range of 80-10,900 ppm. ATA-100 showed the highest sensitivity for ethyl butyrate. The results have confirmed the possibility of utilizing ATA-100 COP-based surface acoustic wave (SAW) sensors for a wide variety of applications, including indoor air quality and environmental monitoring of volatile organic compounds (VOCs).
ABSTRACT
In this study, reduced graphene oxide (rGO) was prepared using a green ultrasonic microwave assisted method and investigated rGO based non-enzymatic electrochemical sensor for detecting a synthetic fungicide as a propamocarb (PM) pesticide. The rGO-based sensor exhibited rapid response within 1 min, low detection limit of 0.6 µM and wide linear range of (1-5) µM with a high sensitivity of 101.1 µAµM-1 cm-2 for PM. Besides this, the sensor detected the propamocarb pesticide on the real cucumber sample with high sensitivity in the concentration range of (1-5) µM within a 1-minute cycle. The sensor is highly selective against propamocarb pesticide. The prepared non-enzymatic electrochemical sensor exhibited high sensitivity, high selectivity, reproducibility, and rapid response.
Subject(s)
Fungicides, Industrial , Graphite , Pesticides , Carbamates , Electrochemical Techniques , Electrodes , Reproducibility of ResultsABSTRACT
Sewage treatment works are one of the major sources that cause atmospheric odour pollution. The increase in the number of complaints about odour nuisance is due to the increase in environmental concerns. Unfortunately, the legislation on odour nuisance from sewage treatment works is very limited. In order to determine suitable thresholds on which to base legal standards, reliable and efficient odour measurement methods need to be defined. A chemical sensor array was developed for the purpose of measuring wastewater odour. This paper describes the development of the chemical sensor system which is specifically tuned to odours of wastewater origin and which can give an electronic measure of the wastewater odours. Odour emissions from a wastewater treatment facility were detected by using a quartz crystal microbalance (QCM) sensor array. The array consists of nine sensor elements, which were coated with different materials. In this paper, the usage of these novel instruments in the water industry was shown.
