DFT study on MgAl-layered double hydroxides with different interlayer anions: structure, anion exchange, host–guest interaction and basic sites

. The interactions between interlayer species and the host layer or the interlayer water molecules are mainly derived from the electrostatic interactions. The main components of the valence band maximum (VBM) and conduction band minimum (CBM) of MgAl-LDHs are derived from p orbitals of halogen anions or the O-2p orbitals of other anions, and the Mg-2p orbital, respectively. This illustrates that the most basic sites of MgAl-LDHs are the interlayer anions rather than the hydroxyl group in the layer, while the most acidic sites are Mg in the layers. And LDHs containing anions with higher charge show stronger basicity. The calculation results agree well with the experimental findings. This work provides effective theoretical information for the design and preparation of the anion-controlled functional LDHs or related materials with prospective applications.