Study of the adsorption of single and multiple CO molecules on pristine and Fe-doped 4-12-4-graphyne surfaces by density functional theory

Abstract

Carbon monoxide (CO) is one of the common toxic gases used in human production and life. Exploring effective materials for CO gas detection has been the focus of researchers’ attention. In this paper, density functional theory is used to study the CO adsorption properties on pristine square 4-12-4-graphyne (4-12-4-GY) and Fe-doped 4-12-4-graphyne (Fe-4-12-4-GY). According to the calculations, CO is only physisorbed on the pristine 4-12-4-GY. 4-12-4-GY with Fe doping opens the band gap and retains some symmetry. After doping, the adsorption capacity of CO on Fe-4-12-4-GY is obviously increased with chemisorption, and the adsorption energy and charge transfer are −1.576 eV and 0.167 e, respectively. In addition, the presence of mirror-symmetric adsorption sites for Fe-4-12-4-GY enables the effective adsorption of up to three CO molecules. The results of this study will help to advance the study of the adsorption of multiple gas molecules on two-dimensional carbon materials, which will be of guidance for the design of CO gas sensors.