First-principles insight into adsorption behavior of a Pd-doped PtTe2 monolayer for CO and C2H2 and the effect of an applied electric field

Abstract

Using first-principles theory, we propose a Pd-doped PtTe2 (Pd–PtTe2) monolayer as an outstanding sensing material for CO and C2H2 to estimate the operational condition of oil-immersed transformers. A Te atom of the pristine PtTe2 monolayer is substituted by a Pd atom to model the Pd–PtTe2 structure and the calculated formation energy is −0.013 eV. The Pd–PtTe2 monolayer conducts chemisorption of CO but physisorption of C2H2 with adsorption energies of −1.121 and −0.740 eV, respectively. The electronic properties show the sensing mechanism and bonding behavior in the gas adsorptions, while the analyses of band structure and recovery property show the potential of the Pd–PtTe2 monolayer as a room-temperature C2H2 sensor, and a reusable CO sensor following a heating process of 34 min. Moreover, the applied electric fields can effectively modulate the bandgap of the gas systems, uncovering the promoted sensing response under positive electric fields. This work explores the PtTe2-based nano-surfaces for gas-sensing application in electrical power systems, which paves the way for further investigation on the PtTe2 monolayer for applications in the fields of electrical engineering and gas sensing generally.