Ab initio study of hydrogen adsorption on benzenoid linkers in metal–organic framework materials

• Published in: Journal of physics. Condensed matter 2007-09, Vol.19 (38), p.386220-386220 (8)
• Main Authors: Gao, Yi, Zeng, X C
• Format: Article
• Language: English
• Subjects: Condensed matter: electronic structure, electrical, magnetic, and optical properties; Electron states; Exact sciences and technology; Methods of electronic structure calculations; Physics
• ISSN: 0953-8984; 1361-648X
• DOI: 10.1088/0953-8984/19/38/386220

We have computed the energies of adsorption of molecular hydrogen on a number of molecular linkers in metal-organic framework solid materials using density functional theory (DFT) and ab initio molecular orbital methods. We find that the hybrid B3LYP (Becke three-parameter Lee-Yang-Parr) DFT method gives a qualitatively incorrect prediction of the hydrogen binding with benzenoid molecular linkers. Both local-density approximation (LDA) and generalized gradient approximation (GGA) DFT methods are inaccurate in predicting the values of hydrogen binding energies, but can give a qualitatively correct prediction of the hydrogen binding. When compared to the more accurate binding-energy results based on the ab initio Moller-Plesset second-order perturbation (MP2) method, the LDA results may be viewed as an upper limit while the GGA results may be viewed as a lower limit. Since the MP2 calculation is impractical for realistic metal-organic framework systems, the combined LDA and GGA calculations provide a cost-effective way to assess the hydrogen binding capability of these systems.