Computational Study of CO2 Adsorption on Metal Doped ZrO2

Abstract

Many studies have been done for the adsorption of CO2 using metal oxide materials in the aim of reducing anthropogenic CO2 emission. Zirconium dioxide (ZrO2) has gained much interest as a potential candidate for CO2 adsorption materials due to high mechanical strength and promoter-less CO2 adsorption. Pure ZrO2, however, shows low reactivity in CO2 adsorption. In this study, CO2 adsorption on ZrO2 with dopant species was studied by using density functional theory calculations. Zn2+, Mg2+, Ca2+, Fe2+ and Fe3+ ions were selected as dopants and their effects on the adsorption were investigated. The adsorption energy of CO2 and adsorbed sites were first determined. The results showed that CO2 was most stably adsorbed on Mg doped ZrO2 surface and interacted in a form of tridentate with parallel direction on the surface. Interestingly, dopants residing in the sublayer of ZrO2 induced more stable adsorption energy than dopants in top layer did. In terms of doping concentrations, CO2 was physisorbed in most of adsorption sites when the concentration increased.