Abstract
Nickel cations have been introduced into framework sites of the magnesium dioxiterephthalate MOF, CPO-27(Mg), via a procedure involving post-synthetic treatment with an aqueous solution of Ni2+ cations and a weak acid. The final solids have Ni concentrations up to 70 mol% of the total cation content. Selected area EDX analysis, synchrotron X-ray powder diffraction and XPS surface analysis indicate that Ni2+ is distributed throughout the crystals with highest concentration at the external surface. A mechanism involving both crystallisation and predominant isomorphous cation replacement is proposed. The modified solids have much enhanced adsorption capacities following simple thermal evacuation under vacuum than unmodified CPO-27(Mg), particularly for N-2 at 77 K, for which uptakes of 17 mmol g(-1) are achieved. This is attributed to surface modification that makes the surface more stable to heating under evacuation.
Original language | English |
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Pages (from-to) | 9779-9786 |
Number of pages | 8 |
Journal | CrystEngComm |
Volume | 15 |
Issue number | 45 |
DOIs | |
Publication status | Published - 2013 |
Keywords
- METAL-ORGANIC FRAMEWORKS
- MICROPOROUS COORDINATION POLYMERS
- CARBON-DIOXIDE
- HYDROGEN ADSORPTION
- FLUE-GAS
- EXCHANGE
- CRYSTAL
- LIGAND
- SITES
- CO2