Enhanced adsorption mechanism of carbonyl-containing volatile organic compounds on Al-decorated porous graphene monolayer: A density functional theory calculation study

Abstract

Volatile organic compounds (VOCs) are a type of typical toxic and harmful air pollutants. Among many abatement techniques for VOCs, there is no doubt that adsorption technology is cost-effective one. In this work, to understand the adsorption mechanisms of VOCs on porous graphene (PG) monolayer and Al-modified PG system, density functional theory (DFT) calculations are performed. Our results suggest that PG monolayer has promising adsorption performance to VOCs molecules with relatively strong adsorption energy. While Al-decorated porous graphene monolayer can obviously enhance the adsorption energies of carbonyl-containing volatile organic compounds (CVOCs) by nearly 2 times, but only slight changes for other VOCs. Projected electronic density of states (PDOS), electronic distribution and Mulliken charge analysis show that the decoration of Al atom induces chemical bonding between the O atom in carbonyl of CVOCs and Al-decorated PG substrate, which enhances its adsorption capacity remarkably. The computational work proposes a promising adsorbent for selective VOCs removal, and also provides theoretical guidance for high performance VOCs adsorbents design.