Tunable Gas Sensing Properties of Noble Metal‐Doped PC ₃ Monolayers: A Density Functional Theory Study of NH ₃ , NO ₂ , and NO Adsorption

This study employs density functional theory (DFT) to systematically investigate the interaction of NH 3 , NO 2 , and NO gases with noble metal‐doped (Pt, Pd) PC 3 monolayers. A detail geometry optimization, self‐consistent field calculations, and electronic structure analysis, the structural adaptations, adsorption behaviors, and charge transfer dynamics are investigated at the gas‐material interface. The near‐zero bandgap and overlapping bands in Pt/Pd‐doped systems confirm a metallic nature, while the projected density of states analysis reveals distinct orbital contributions near the Fermi level for different systems. Our results reveal distinct adsorption behavior, i.e., NO 2 acts as an electron acceptor with a strong binding energy of −2.82 eV on the Pt–PC 3 surface, while NH 3 serves as an electron donor to the Pt–PC 3 surface. The Pt‐doped monolayer demonstrates superior affinity for NO 2 compared to its Pd‐doped counterpart, highlighting its potential as a highly selective sensor material. Our results highlight the crucial role of metal dopants in tuning the sensing properties of PC 3 monolayers. These insights provide a foundation for designing advanced gas‐sensing platforms using tunable 2D materials.