New insights into the breathing phenomenon in ZIF-4
| Autor: | Anibal J. Ramirez-Cuesta, Alexander Missyul, Jesus Gandara-Loe, Yongqiang Cheng, François Fauth, Joaquín Silvestre-Albero, Luke L. Daemen, Peter I. Ravikovitch |
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| Přispěvatelé: | Universidad de Alicante. Departamento de Química Inorgánica, Universidad de Alicante. Instituto Universitario de Materiales, Materiales Avanzados |
| Rok vydání: | 2019 |
| Předmět: |
Diffraction
Química Inorgánica Materials science Renewable Energy Sustainability and the Environment 02 engineering and technology General Chemistry 021001 nanoscience & nanotechnology Co2 adsorption Inelastic neutron scattering Synchrotron law.invention ZIF-4 Breathing phenomenon Adsorption Chemical physics law Molecule General Materials Science 0210 nano-technology Entropy (order and disorder) |
| Zdroj: | RUA. Repositorio Institucional de la Universidad de Alicante Universidad de Alicante (UA) |
| ISSN: | 2050-7496 2050-7488 |
| Popis: | Structural changes in ZIFs upon adsorption remain a paradigm due to the sensitivity of the adsorption mechanism to the nature of the organic ligands and gas probe molecules. Synchrotron X-ray diffraction under operando conditions clearly demonstrates for the first time that ZIF-4 exhibits a structural reorientation from a narrow-pore (np) to a new expanded-pore (ep) structure upon N2 adsorption, while it does not do so for CO2 adsorption. The existence of an expanded-pore structure of ZIF-4 has also been predicted by molecular simulations. In simulations the expanded structure was stabilized by entropy at high temperatures and by strong adsorption of N2 at low temperatures. These results are in perfect agreement with manometric adsorption measurements for N2 at 77 K that show the threshold pressure for breathing at ∼30 kPa. Inelastic neutron scattering (INS) measurements show that CO2 is also able to promote structural changes but, in this specific case, only at cryogenic temperatures (5 K). The authors would like to acknowledge financial support from the MINECO (MAT2016-80285-p), Generalitat Valenciana (PROMETEOII/2014/004), H2020 (MSCA-RISE-2016/NanoMed Project), Spanish ALBA synchrotron (Projects AV-2017021985 and IH-2018012591) and Oak Ridge beam time availability (Project IPTS-20843.1). JSA and JGL acknowledge financial support from UA (ACIE17-15) to cover all the expenses for INS measurements at Oak Ridge. JGL acknowledges GV (GRISOLIAP/2016/089) for the research contract. |
| Databáze: | OpenAIRE |
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