Density functional theory study on the enhanced adsorption mechanism of gaseous pollutants on Al-doped Ti2CO2 monolayer

Abstract

Inorganic toxic gases (ITGs) and volatile organic compounds (VOCs) are two kinds of typical hazardous gaseous pollutants harming human health. The removal of them is still an enormous challenge. Based on density functional theory (DFT) calculations in this work, Al-doped Ti2CO2 (ATCO), a single-atom-decorated MXene, is expected to be a more effective adsorbent for these gases than pristine Ti2CO2 (TCO) due to the outstanding adsorption capacity and superb electrical properties. We then shed light on the mechanism of enhanced adsorption by ATCO. The results of Mulliken charge analysis, partial density of states (PDOS) and deformation charge density (DCD) confirm the change of charge distribution on ATCO surface after the decoration of Al atom. Obviously, Al atom can act as a bridge to promote the formation of chemical bonds between the adsorbed gases and ATCO substrate. This work not only provides a promising material for the adsorption of gaseous pollutants, but also explores a new avenue for designing and fabricating MXene-based non-noble metal materials in the area of gas adsorbents.