Adsorption effects of acetone and acetonitrile on defected penta-PdSe₂ nanoribbons: a DFT study

Using DFT calculations, the structural and electronic properties of the ZZ7 p-PdSe₂ nanoribbons (ZZ7) with the four kinds of vacancy defects, including ZZ7-V_Pd, ZZ7-V_Se, ZZ7-V_Pd+Se, and ZZ7-V_2Se are studied, in which their stability, diverse geometries, and altered electronic properties are determined through the formation energies, optimal structural parameters, electronic band structures, and DOSs. Specifically, the formation energies of all studied systems show significant negative values around -3.9 eV, evidencing their good thermal stability. The geometries of four defective structures exhibit different diversification, whereas only the ZZ7-V_2Se structure possesses the highly enhanced feature, identified as the most effective substrate for the acetone and acetonitrile adsorption. On the electronic behaviors, the ZZ7 band structure displays the nonmagnetic metallic characteristics that become the ferromagnetic half-metallic band structures for the ZZ7-V_Pd and ZZ7-V_Se and the ferromagnetic semi-metallic band structures for the ZZ7-V_Pd+Se and ZZ7-V_2Se. For adsorption of the acetone and acetonitrile on the ZZ7-V_2Se structure, the energetic stability, adsorption sites, adsorption distances, charge transfers, and electronic characteristics of the adsorbed systems are determined by the adsorption energies, optimal adsorption sites, adsorption distances, Mulliken populations, and DOSs. The adsorption energies of the acetone- and acetonitrile-adsorbed ZZ7-V_2Se systems display significant values at -1.2 eV and -0.86 eV at the preferable sites of 8 and 11, respectively, indicating their great adsorption ability. The adsorption mechanism of the acetone- and acetonitrile-adsorbed systems belongs to the physisorption owing to absence of chemical bonds, in which the bond lengths of the ZZ7-V_2Se substrate show a very small deviation. Under the acetone and acetonitrile adsorptions, the ferromagnetic semi-metallic DOSs of the ZZ7-V_2Se become the ferromagnetic half-metallic DOSs for the ZZ7-V_2Se-acetone-8 and the ferromagnetic semiconducting DOSs for the ZZ7-V_2Se-acetonitrile-11. Our systematic results can provide a complete understanding of the acetone- and acetonitrile adsorptions on the potential ZZ7-V_2Se structure, which is very useful for nanosensor application.