Density functional theory investigation of the enhanced adsorption mechanism and potential catalytic activity for formaldehyde degradation on Al-decorated C2N monolayer

Carbonyl compounds, in particular formaldehyde (HCHO), are among the most common indoor air pollutants that have been found to be toxic to humans. Thus, in this study, density functional theory (DFT) calculations are performed to study the adsorption properties of HCHO on pristine and Al-decorated C2N monolayer. The results indicate that Al-decorated C2N has a strong adsorption ability for HCHO molecules with an adsorption energy of -2.585 eV. Moreover, partial density of states (PDOS), Mulliken atomic charges, and electron density distributions are calculated to investigate the adsorption enhancement mechanism. The results show that the Al atom serves as a bridge to connect the adsorbed molecules and the C2N monolayer, thus strengthening the adsorption. Furthermore, we study the adsorption of H2O and O-2 with the possible generation of hydroxyl (center dot OH) and superoxide (O-2(center dot-) ) radicals, which are active for HCHO degradation; the results show that both molecules can also be strongly adsorbed on the Al-decorated C2N surface. In particular, the dissociation of H2O provides an excellent precondition for the generation of hydroxyl radicals. Our findings suggest that Al-decorated C2N can be a promising material for the adsorption and subsequent catalytic degradation of HCHO molecules. (C) 2019, Dalian Institute of Chemical Physics, Chinese Academy of Sciences. Published by Elsevier B.V. All rights reserved.