Adsorption performance of harmful gas molecules over copper decorated aluminene: a DFT study

Detecting hazardous and toxic gases and their removal from environment is essential for human health. 2D materials plays vital role for gas sensing or scavenging. Density functional theory (DFT) was applied to investigate the adsorption of six toxic gases (CO, COS, NO, NO₂, CH₄O, and CH₂N₂) on Cu-decorated Aluminene surface. Aluminene preserve its metallic character after copper decoration. The greater values of adsorption energy (-2.72 eV, -0.92 eV, -3.39 eV, -2.14 eV, -2.66 eV and − 2.95 eV respectively) proposed that Cu-decoration is favorable than pristine Aluminene. Electronic properties and adsorption energies suggested chemisorption behavior of CO, NO and NO₂ while other gas molecules showed physisorption. Hybridization occurs between d-orbitals of the system and the gas molecules that improved the electronic properties. The study encompassed analyses of Density of States (DOS), charge distribution, Electron Localization Function (ELF), work function, charge density difference (CDD) and recovery time. Band gap found to be zero for the optimized system prior to and following gas adsorption. It represent good conductivity of the material, owing to the possibility of an efficient gas sensor. The recovery time analysis indicated that the material exhibited reversible gas sensing properties at high temperatures. At lower temperatures, it could potentially serve as a disposable sensor for industrial safety applications.