Highly Selective Ethyl Mercaptan Sensing Using a MoSe₂/SnO₂ Composite at Room Temperature

Abstract

Volatile organic sulfur compounds (VOSCs) serve not only as biomarkers for dental diseases such as halitosis but also as a tracer for monitoring air quality. Room-temperature selective detection and superior sensitivity against VOSCs at a sub-ppm level has remained a challenging task. Here, we propose a heterostructure-based design using a MoSe 2 /SnO 2 composite for achieving sensitive and selective detection of ethyl mercaptan at room temperature. The composite was synthesized via a facile two-step method. A composite-based device has shown detection down to 1 ppm of ethyl mercaptan over a wider range of relative humidity (40−90%). Notably, the composite has shown adsorption selectivity toward ethyl mercaptan compared to hydrogen sulfide and other reducing or oxidizing analytes. Moreover, a density functional theory (DFT) study has been performed to understand the adsorption selectivity, charge transfer, and modification in the electronic properties after molecule adsorption on the host surface. Simulations predicted the lowest negative adsorption energy for ethyl mercaptan, implying the chemisorption (−142.029 kJ mol −1 ) process of adsorption. The device thus-obtained has also shown a stable response even at an extreme relative humidity level of 90%. The obtained results and superior signal-to-noise ratio indicate that a MoSe 2 /SnO 2 -based sensor may be a promising candidate for highly selective and sensitive detection of ethyl mercaptan even below 1 ppm.

Humidity-Tolerant Room-Temperature Selective Dual Sensing and Discrimination of NH3 and NO Using a WS2/MWCNT Composite

“…Electrical and gas sensing properties of devices were analyzed in a home-assembled static sensing apparatus as shown in Figure S1. A detailed description of the sensing setup can be found in our previous reports. , Figure S2 shows a digital image of two-terminal devices used for these measurements. Ammonia (NH 3 ), carbon monoxide (CO), hydrogen sulfide (H 2 S), chlorine (Cl 2 ), nitric oxide (NO), nitrogen dioxide (NO 2 ), and hydrogen (H 2 ) gas cylinders were obtained from Chemitron Science Laboratory (India).…”

Ultrasensitive Room-Temperature NO2 Detection Using SnS2/MWCNT Composites and Accelerated Recovery Kinetics by UV Activation

“…Gas sensing properties of sensors were investigated in a home-built static sensing setup shown in Figure S1. A detailed description of the sensing setup can be found in our previous reports. , Nitrogen dioxide (NO 2 ), carbon monoxide (CO), chlorine (Cl 2 ), and ammonia (NH 3 ) gas cylinders were obtained from Chemtron Science Laboratory (India). Other vapors of various concentrations were produced by evaporating pure ethanol (99.8%), acetone (99.5%), chloroform (99%), N , N -dimethylformamide (DMF, 99.5%), and formaldehyde (FMD, 40 wt % in H 2 O).…”

“…For gaseous components, a desired volume of the gas was injected into the test chamber using a high-precision syringe. For these gases, the concentration of gas molecules inside the test chamber was calculated using eq , where C c is the required concentration in the test chamber, V is the volume of the test chamber (1 L), and C p (1000 ppm) and V s are the known concentration of gas in the purchased cylinder and the volume of the gas taken in a syringe, respectively. , For ethanol, acetone, formaldehyde, and DMF, eq S1 (Supporting Information) was used to calculate the concentration in ppm. UV irradiation (2.3 mW/1 cm × 0.5 cm) was carried out over the sensor device and applied as needed.…”

“…For gaseous components, a desired volume of the gas was injected into the test chamber using a high-precision syringe. For these gases, the concentration of gas molecules inside the test chamber was calculated using eq , C normalc × V = C normalp × V normals where C c is the required concentration in the test chamber, V is the volume of the test chamber (1 L), and C p (1000 ppm) and V s are the known concentration of gas in the purchased cylinder and the volume of the gas taken in a syringe, respectively. , For ethanol, acetone, formaldehyde, and DMF, eq S1 (Supporting Information) was used to calculate the concentration in ppm. UV irradiation (2.3 mW/1 cm × 0.5 cm) was carried out over the sensor device and applied as needed.…”

Facile hydrothermal synthesis of layered 1T′ MoTe2 nanotubes as robust hydrogen evolution electrocatalysts

“…Layered transition metal dichalcogenides (TMDs) have attracted considerable attention in recent decades because of their novel structures and fascinating physical and chemical properties (Mas-Balleste et al, 2011;Xu et al, 2013;Tan et al, 2017;Ji and Choi, 2022). The layered structure consists of a transition metal atom sheet sandwiched between two sheets of chalcogen atoms, such as MX 2 (M = W, Mo and X = S, Se, Te) (Qian et al, 2014;Sun et al, 2015), which has broad prospects for applications in optoelectronics (Khan and Leuenberger, 2018), photodetection (Malik et al, 2022), nanoelectronics (Wang et al, 2012) and electrochemistry (Chia et al, 2015), and has been well-studied in WS 2 , MoS 2 and MoSe 2 based 2D nanostructures in recent years (Bonaccorso et al, 2015;Zhang et al, 2016;Manzeli et al, 2017;Jha et al, 2019;Han et al, 2020;Singh et al, 2022a;Singh et al, 2022b). In particular, with the demand for effective catalysts for clean energy hydrogen production, TMDs have been widely studied and are considered to be as one of the most outstanding electrocatalysts for the hydrogen evolution reaction (HER) (Jin et al, 2018;Fu et al, 2021;Zhang et al, 2021;Li et al, 2022).…”