First-principles screening upon Pd-doped HfSe2 monolayer as an outstanding gas sensor for DGA in transformers

Abstract

Based on the first-principles theory, this work studies the Pd-doping behavior on the HfSe2 surface through the Se-substitution manner and the sensing potential of Pd-doped HfSe2 (Pd-HfSe2) monolayer upon CO and C2H2, in order to explore its application for dissolve gas analysis (DGA) in the transformer oil. Our results show that the formation energy (Eform) for Pd-doping is obtained as 1.20 eV and Pd-doping enlarges the bandgap of pure HfSe2 system from 0.476 to 0.798 eV for the Pd-HfSe2 system. For gas adsorption, chemisorption is identified for the CO system while physisorption for the C2H2 system. The bandgap of the Pd-HfSe2 monolayer is declined to 0.730 and 0.746 eV for the CO and C2H2 system, respectively, obtaining the electrical response (S) of −73.4% and −63.7%, respectively. Moreover, the CO and C2H2 could be feasibly desorbed from the Pd-HfSe2 surface at the room temperature, which enables the reusability of such sensor for gas detection again. Our calculations explore the strong potential of Pd-HfSe2 monolayer for gas sensing application given its favorable sensing and desorption property upon CO and C2H2, which would be beneficial for possible application in the field of electrical engineering soon.