A Theoretical Investigation of Cu+, Ni2+ and Co2+-Exchanged Zeolites for Hydrogen Storage

Ozbek M. O., İPEK TORUN B.

ChemPhysChem, vol.23, no.20, 2022 (SCI-Expanded) identifier identifier identifier

  • Publication Type: Article / Article
  • Volume: 23 Issue: 20
  • Publication Date: 2022
  • Doi Number: 10.1002/cphc.202200272
  • Journal Name: ChemPhysChem
  • Journal Indexes: Science Citation Index Expanded (SCI-EXPANDED), Scopus, PASCAL, Biotechnology Research Abstracts, Chemical Abstracts Core, Chimica, Compendex, EMBASE, INSPEC, MEDLINE
  • Keywords: cobalt, DFT, hydrogen storage, nickel, zeolites
  • Kocaeli University Affiliated: No

Abstract

© 2022 Wiley-VCH GmbH.This study investigates the H2 adsorption on Cu+, Ni2+ and Co2+-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 Ni2+ and Co2+ 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. H2 adsorption was investigated for all the Cu+, Ni2+ and Co2+ centers. AEI and CHA resulted in similar H2−Cu interactions for the Al and B substituted structures. H2 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 H2 antibonding orbital (σH2*). The H2 adsorption energies on the Ni2+ and Co2+-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 Co2+ and Ni2+ cations resulted in heat of H2 adsorption close to optimum values required for H2 storage on porous materials.