Reversible adsorption/desorption of the formaldehyde molecule on transition metal doped graphene by controlling the external electric field: first-principles study

Adsorption of formaldehyde molecule on the pristine or transition metal doped graphene is theoretically investigated using density functional theory method. The most stable adsorption structures, adsorption energy, Mulliken charge, and the electronic property are analyzed in details. The results show that the interaction between the formaldehyde and pristine graphene is weak physisorption, but the introduction of metal atom in graphene strengthens the adsorption of formaldehyde molecule on the material. As we know, overmuch adsorption makes the adsorbent hard to recover and recycle. It is found in the present work that the recovery of graphene substrate can be achieved by controlling the direction of the external electric field. In addition, electronic property of the substrate has a significant change after formaldehyde molecule adsorption, which makes transition metal doped graphene material a potential sensor for formaldehyde. The effect of humid environment on the interaction between the formaldehyde molecule and Mn-doped graphene sheet is also explored. The calculated results reveal that the adsorption strength of the formaldehyde molecule is weakened when the water molecules exist in the environment. However, this negative effect can be ameliorated by controlling the electric field of the system. These conclusions would provide some beneficial guidance to the related experiments and application in future.