Porous ZnO-graphenylene sheet for acetylacetone detection

Abstract

An experimental group (Liu et al., 2019) demonstrated the synthesis of a porous ultrathin ZnO nanosheet that exhibits improved acetylacetone (Acac) sensing performance due to numerous oxygen vacancies on the surface. Using van der Waals interactions corrected first-principles density functional theory (DFT) calculations, we investigated a porous ZnO (inorganic graphenylene) monolayer that extended the allotropes of the synthesized biphenylene structure for detection and anchoring of the Acac molecule. The calculated Eads (0.97 eV) value indicates that the Acac molecule chemisorbs on the ZnO (Acac-ZnO) system and the Eads (3.11 eV) value for hydrated Acac adsorbed ZnO (ZnO-Acac-H2O) system significantly improved. Bader charge analysis indicate that the ZnO monolayer receives charge from both Acac and Acac-H2O. The band gap of ZnO (2.38 eV) decreases slightly to 2.31 eV and 2.23 eV for Acac-ZnO and ZnO-Acac-H2O cases, respectively. We found that adsorption of pure and hydrated Acac on the ZnO monolayer decreased the workfunction, indicating an increased probability of electron mobility. The estimated libration frequency values indicate that the Acac will preferentially chemisorbed in a parallel orientation on the ZnO monolayer, providing a spectral signature for the experimental location of the Acac on ZnO monolayer. Our results provide a detailed theoretical guide for the design of the porous ZnO monolayer as a substrate to detect and anchor the acetylacetone molecule.