DFT study of H2 adsorption at Cu-SSZ-13 zeolite: a cluster approach

In this work the H2 adsorption at a Cu(I)-SSZ-13 exchanged zeolite was theoretically investigated. A systematic cluster approach was used and different density functionals (B3LYP, B3LYP-D3(BJ), M06L, PBE, PBE-D3(BJ) and ωB97XD) and def2-SVP basis set were benchmarked. In order to select the best approach to the H2 adsorption over a Cu(I)-SSZ-13 cluster with 78 atoms (16 T-sites), two main tasks were performed: (i) a comparison between theoretical and experimental structures and (ii) a comparison between theoretical and experimental adsorption enthalpies. By employing the most suitable functional - the ωB97X-D - the H2 interaction with the zeolite structure was studied by means of NBO, NCI, AIM and DLPNO-CCSD(T)/LED analyses.