First-principles study of acetone adsorption on Cu-vacancy-engineered CuO surface for highly selective sensing

• Density Functional Theory formalism was employed to study acetone behavior on pristine and defective CuO (1 1 1) surfaces. • The localized states created by Cu vacancies near the Fermi level, enhancing charge transfer and chemisorbed interactions. • The device shows selectivity owing to changing the diagram band. • The Cu-4 s orbital shown by PDOS is responsible for charge transfer and conductivity changes. Achieving high sensitivity and selectivity in detecting acetone is a significant challenge in the development of metal oxide-based gas sensors. In this study, density functional theory (DFT) simulations were used to examine the adsorption of acetone on both pristine and defective CuO (1 1 1) surfaces. The findings indicate that pristine CuO has weak physisorption with adsorption energy of −0.524 eV. In contrast, the presence of a copper vacancy increases the interaction strength to −0.782 eV, which is attributed to localized states near the Fermi level and enhanced charge transfer. Analyses of charge density and projected density of states (PDOS) further confirm a more robust electronic response in defective surfaces. Importantly, Cu vacancy also boosts selectivity, as the adsorption energies for competing gases (e.g., H 2 O, CO 2 , N 2 ) are significantly lower, leading to a ∼0.5 eV difference in adsorption energy. These results provide a theoretical foundation for utilizing defect-engineered CuO surfaces as highly sensitive and selective platforms for acetone detection, with potential applications in medical diagnostics like breath analysis for diabetic ketoacidosis.