A Theoretical Investigation of Cu + , Ni 2+ and Co 2+ ‐Exchanged Zeolites for Hydrogen Storage

• Published in: Chemphyschem 2022-10, Vol.23 (20)
• Main Authors: Ozbek, M. Olus, Ipek, Bahar
• Format: Article
• Language: English
• ISSN: 1439-4235; 1439-7641
• DOI: 10.1002/cphc.202200272

This study investigates the H 2 adsorption on Cu + , Ni 2+ and Co 2+ ‐exchanged SSZ‐13 (CHA) and SSZ‐39 (AEI) using periodic DFT computations. The most stable Cu + position was found to be the 6‐membered‐ring window for both zeolites. Similarly, for the investigated Ni 2+ and Co 2+ loadings on 6‐membered‐ring windows, the third nearest neighbor Al positions, i. e., Al−O−Si−O−Si−O−Al coordination, was found to be the most stable position. H 2 adsorption was investigated for all the Cu + , Ni 2+ and Co 2+ centers. AEI and CHA resulted in similar H 2 −Cu interactions for the Al and B substituted structures. H 2 adsorption on Cu + located in the 8‐membered‐ring gave the highest adsorption energy for both frameworks. Replacing Al with B in the framework increased the electron back donation from Cu + (3d) orbitals to H 2 antibonding orbital (σ H2 * ). The H 2 adsorption energies on the Ni 2+ and Co 2+ ‐exchanged zeolites were found to be between −15 and −44 kJ/mol. Higher energy values were observed on the AEI framework, especially when two Al atoms have the Al−O−Si−O−Al configuration. Lesser interaction of the d‐orbitals in the case of the Co 2+ and Ni 2+ cations resulted in heat of H 2 adsorption close to optimum values required for H 2 storage on porous materials.