Adsorption of ammonia on ZrOx-modified graphene nanoribbon: a first-principle investigation

Ahmad I Ayesh; Maitha D El-Muraikhi

doi:10.1007/s00894-022-05417-z

Adsorption of ammonia on ZrO_x-modified graphene nanoribbon: a first-principle investigation

J Mol Model. 2022 Dec 22;29(1):15. doi: 10.1007/s00894-022-05417-z.

Authors

Ahmad I Ayesh¹, Maitha D El-Muraikhi²

Affiliations

¹ Physics Program, Department of Mathematics, Statistics and Physics, College of Arts and Sciences, Qatar University, P. O. Box 2713, Doha, Qatar. ayesh@qu.edu.qa.
² Physics Program, Department of Mathematics, Statistics and Physics, College of Arts and Sciences, Qatar University, P. O. Box 2713, Doha, Qatar.

Abstract

Ammonia (NH₃) is a main environmental pollutant related to global warming, and reduction of its emission is the subject of multiple international agreements and regulations. Accordingly, the development of highly precise detectors to monitor its content in the environment is essential to track and limit its emission. This work examines the influence of modifying of armchair-graphene nanoribbon (AGNR) by zirconium (Zr) and its oxides on its adsorption for NH₃ gas. Density functional theory (DFT) computations are utilized to investigate the band structure, adsorption energy ([Formula: see text]), adsorption length ([Formula: see text]), charge transferred ([Formula: see text]), and density of states (DOS) of pristine and modified structures with ZrO_x ([Formula: see text]). ZrO_x is presented to AGNR nanostructure by two pathways: substitution of carbon atoms (doping) and introduction on top of the AGNR surface (decoration). The findings of the investigation illustrate great improvement of NH₃ adsorption on AGNR due to its modification. Although the adsorption energy is enhanced in general upon modification, AGNR structures where ZrO_x substitute carbon atoms exhibit greater adsorption energy as compared with the decoration scheme. The maximum energy of adsorption is for the AGNR structure doped with ZrO₂, followed by that doped with Zr. The adsorption energy of NH₃ on the ZrO₂-doped AGNR is - 10.05 eV with an adsorption length of 2.4 Å and - 0.214e charge transferred. As compared to the pristine structure, the adsorption energy for NH₃ on AGNR doped with ZrO₂ increases 22.2 times. Therefore, AGNR nanostructure doped with ZrO_x can be considered for practical sensors for the applications of detection and control of ammonia emission.

Keywords: Ammonia sensor; DFT; Graphene nanoribbon; ZrOx.