Tailoring the Gas Sensing Performance of ZrS2 Monolayers via Noble Metal Doping for Thermal Runaway Gas Detection in LIBs: A First-Principles Study

Real-time detection of thermal runaway gases is essential for establishing reliable early warning systems for LIB safety. In this work, we investigate the adsorption behaviors, electronic properties, and gas sensing mechanisms of noble metal (Au and Pt)-doped ZrS2 monolayers toward four typical thermal runaway gases (H2, CO, C2H2, and C2H4) using first-principles theory. Specifically, we comprehensively evaluate the adsorption energy, charge transfer, band structure, density of states, recovery time, and sensing response of two doped systems upon four gas species, in order to establish a multi-parameter framework for preferring dopant determination. Our findings reveal that both Au- and Pt-doped systems exhibit enhanced adsorption performance relative to the pristine ZrS2 monolayer. Notably, the Pt dopant promotes chemisorption toward CO and C2H4 through the formation of Pt–C chemical bonds. In contrast, the Au dopant exhibits chemisorption exclusively toward C2H4, while the other three gases remain physisorbed. The combined analysis of bandgap variation-modulated sensing response and the adsorption energy-modulated recovery property indicate that the Au-ZrS2 monolayer is a reusable and selective sensing material upon C2H4, while the Pt-ZrS2 monolayer is a more favorable candidate with higher sensitivity and reusability for C2H4, C2H2 and CO sensing. These findings provide a theoretical foundation for the rational design of high-performance ZrS2-based chemiresistive gas sensors through strategic noble metal selection, thus contributing to the advancement of early warning systems for LIB safety.