Rh-Doped ZnO Monolayer as a Potential Gas Sensor for Air Decomposed Species in a Ring Main Unit: A First-Principles...

Using the first-principles theory, this paper studies the Rh-doping behavior on the ZnO monolayer and investigates the adsorption and sensing behaviors of a Rh-doped ZnO (Rh-ZnO) monolayer to NO₂ and O₃ to explore its potential as a gas sensor to evaluate the operation status of the ring main unit in the power system. The results indicate that the Rh dopant can be stably anchored on the T_O site of the ZnO monolayer with an E _b of -2.11 eV. The Rh-ZnO monolayer shows chemisorption of NO₂ and O₃, with E _ad values of -2.11 and -1.35 eV, respectively. Then, the electronic behavior of the Rh-ZnO monolayer before and after gas adsorption is analyzed in detail to uncover the sensing mechanism for gas detection. Our findings indicate that the Rh-ZnO monolayer is a promising resistance-type gas sensor with a higher response to O₃ and can be explored as a field-effect gas sensor with a higher response to NO₂. Our theoretical calculations provide the basic sensing mechanism of the Rh-ZnO monolayer for gas detection and would be meaningful to explore novel sensing materials for gas detection in the field of electrical engineering.