Metal Dimer‐Functionalized WSe 2 Monolayers as Potential Materials For NO and NO 2 Sensing and Purification: A DFT Investigation

ABSTRACT This study investigates the energetic, structural, and electronic properties of monolayers functionalized with various metal dimers (, , , AuAg, AuPt, and AgPt) using density functional theory (DFT). The calculated properties of pristine are consistent with previously reported theoretical and experimental data. Metal dimer decoration introduces new electronic states near the Fermi level and reduces the band gap, leading to significant modifications in the electronic structure. The adsorption behavior of NO and molecules on pristine and decorated surfaces was also analyzed. The results reveal that metal decoration substantially enhances gas adsorption, with ‐functionalized showing the strongest interaction, significant O–N bond elongations, pronounced charge transfer, and strong orbital hybridization, characteristic of chemisorption. Compared to NO, exhibits stronger adsorption, resulting in higher sensitivity and larger work function changes. Recovery time analysis indicates that the adsorption properties depend on both the gas molecule and the metal dimer composition. Moreover, band structure and conductivity analyses show that metal decoration improves the intrinsic conductivity of . These findings highlight the potential of metal dimer‐functionalized monolayers for toxic gas sensing, capture, and air purification applications.