Abstract
CO and CO2 are among the most commonly monitored gases. However, the currently available semiconductor sensors require heating to ∼400 °C in order to operate effectively. This increases the power demand and shortens their lifespan. Consequently, new material prospects are being investigated. The adoption of novel two-dimensional layered materials is one of the pursued solutions. MoS2 and MoTe2 sheets have already been shown sensitive to NO2 and NH3 even at room temperature. However, their response to other compounds is limited. Hence, this work investigates, by employing density functional theory (DFT) calculations, the doping of Al, Si, P, S, and Cl atoms into the Te vacancy of MoTe2, and its impact on the sensing characteristics for CO and CO2. The computations predict that P doping significantly enhances the molecule-sheet charge transfer (up to +436%) while having only a little effect on the adsorption energy (molecular dynamics show that the molecule can effectively diffuse at 300 K). On the other hand, the doping has a limited impact on the adsorption of CO2. The relative (CO/CO2) response of P-doped MoTe2 is 5.6 compared to the 1.5 predicted for the pristine sheet. Thus, the doping should allow for more selective detection of CO in CO/CO2 mixtures.
Highlights
carbon monoxide (CO) and CO2 are among the most commonly monitored gases
Carbon dioxide (CO2) and carbon monoxide (CO) are the principal products of combustion of fossil fuels. Their emissions are extremely prevalent in transportation, electricity production, industrial processes, as well as commercial and residential applications.[1−4] Despite that, both gases can be harmful to human health, with CO being significantly more dangerous than CO2.5,6 CO is formed when carbon in fuel is not burned completely, which makes the optimal supply of oxygen (O2) doubly important
The elements within these three layers bond covalently, while individual three-layer sheets interact with each other via weak van der Waals forces, which allows for their effective exfoliation.[26,27]
Summary
CO and CO2 are among the most commonly monitored gases. the currently available semiconductor sensors require heating to ∼400 °C in order to operate effectively. In the case of S-MoTe2 (Figure 3e), the dopant has the same valence configuration as Te. the doping is predicted to have a limited effect on the electrical properties of the sheet.
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