Adsorption of ammonia on ZrOx-modified graphene nanoribbon: a first-principle investigation
Ahmad I. Ayesh, M. El‐Muraikhi
Abstract
Abstract Ammonia (NH 3 ) 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 NH 3 gas. Density functional theory (DFT) computations are utilized to investigate the band structure, adsorption energy ( $${E}_{d}$$ <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:msub> <mml:mi>E</mml:mi> <mml:mi>d</mml:mi> </mml:msub> </mml:math> ), adsorption length ( $$D$$ <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:mi>D</mml:mi> </mml:math> ), charge transferred ( $$\Delta Q$$ <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:mrow> <mml:mi>Δ</mml:mi> <mml:mi>Q</mml:mi> </mml:mrow> </mml:math> ), and density of states (DOS) of pristine and modified structures with ZrO x ( $$x=0, 1, \mathrm{or }2$$ <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:mrow> <mml:mi>x</mml:mi> <mml:mo>=</mml:mo> <mml:mn>0</mml:mn> <mml:mo>,</mml:mo> <mml:mn>1</mml:mn> <mml:mo>,</mml:mo> <mml:mi>or</mml:mi> <mml:mn>2</mml:mn> </mml:mrow> </mml:math> ). 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 NH 3 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 ZrO 2 , followed by that doped with Zr. The adsorption energy of NH 3 on the ZrO 2 -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 NH 3 on AGNR doped with ZrO 2 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.