Gas-Sensing Performance of Ru- or Rh-Modified ZrS2 Monolayers toward Typical Lung Cancer Biomarker Gases: A DFT Study

Early detection of lung cancer via exhaled breath analysis requires gas-sensing materials with high sensitivity and selectivity. In this work, the sensing performance of Ru- and Rh-modified ZrS2 monolayers toward representative biomarkers (benzene (C6H6), acetone (C3H6O), and isoprene (C5H8)) is systematically investigated using density functional theory (DFT). The results show that transition-metal modification significantly enhances gas adsorption, converting weak physisorption on pristine ZrS2 into strong chemisorption on transition metal (TM)-decorated surfaces. Electronic structure analyses reveal pronounced orbital hybridization and charge transfer between the adsorbed molecules and TM-ZrS2 systems, leading to strong interaction and stable adsorption configurations. Selectivity evaluation indicates that Rh-ZrS2 exhibits excellent anti-interference capability against common exhaled gases, while Ru-ZrS2 shows moderate selectivity with potential interference from O2. Sensitivity analysis based on band gap modulation demonstrates that Ru-ZrS2 is highly responsive to C6H6, whereas Rh-ZrS2 shows superior sensitivity toward C3H6O and C5H8. In addition, recovery time calculations suggest that rapid desorption can be achieved under UV-assisted conditions at elevated temperatures. These results demonstrate that TM-modified ZrS2 monolayers, particularly Rh-ZrS2, are promising candidates for high-performance gas sensors, offering theoretical support for noninvasive lung cancer diagnosis.