Resolving Competitive Adsorption Pathways on Ir-WSe ₂ Nanosheets via DFT Simulations for Ultra-Selective NO Recognition in Harsh Environments

Accurate NO detection in industrial waste gas is often hindered by H 2 O and CO 2 . Therefore, highly selective sensing materials are needed. This study uses density functional theory (DFT). It explores the NO-selective performance of Au-, Pt-, and Ir-modified monolayer WSe 2 nanosheets with H 2 O and CO 2 present. Computational results show small binding energy changes in doped systems, maintaining structural stability. Ir-WSe 2 has the highest binding energy (−5.48 eV). It also has the strongest NO adsorption (−1.77 eV) in a tight configuration. d-band center tuning enhances this adsorption. Crystal Orbital Hamilton Population (COHP) analysis confirms it quantitatively. Density of states (DOS) data show that only NO changes Ir-WSe 2 nanosheets’ electronic structure, enabling detectable signals. Molecular dynamics and thermodynamic analysis confirm stable NO adsorption (proceeding spontaneously at 650 K) and fast H 2 O migration. Thus, Ir-WSe 2 nanosheets have great potential for selective NO detection in industrial waste gas.