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The characteristics of water vapor adsorption depend on the structure, porosity, and functional groups of the material. Metal–organic framework (MOF)-derived carbon (MDC) is a novel material that exhibits a high specific area and tunable pore sizes by exploiting the stable structure and porosity of pure MOF materials. Herein, two types of aluminum-based MOFs were used as precursors to synthesize hydrophobic microporous C-MDC and micro-mesoporous A-MDC via carbonization and activation depending on the type of ligands in the precursors. C-MDC and A-MDC have different pore characteristics and exhibit distinct water adsorption properties. C-MDC with hydrophobic properties and micropores exhibited negligible water adsorption (108.54 mgg−1) at relatively low pressures (P/P0~0.3) but showed a rapid increase in water adsorption ability (475.7 mgg−1) at relative pressures of about 0.6. A comparison with the isotherm model indicated that the results were consistent with the theories, which include site filling at low relative pressure and pore filling at high relative pressure. In particular, the Do–Do model specialized for type 5 showed excellent agreement. [ABSTRACT FROM AUTHOR]

The characteristics of water vapor adsorption depend on the structure, porosity, and functional groups of the material. Metal–organic framework (MOF)-derived carbon (MDC) is a novel material that exhibits a high specific area and tunable pore sizes by exploiting the stable structure and porosity of pure MOF materials. Herein, two types of aluminum-based MOFs were used as precursors to synthesize hydrophobic microporous C-MDC and micro-mesoporous A-MDC via carbonization and activation depending on the type of ligands in the precursors. C-MDC and A-MDC have different pore characteristics and exhibit distinct water adsorption properties. C-MDC with hydrophobic properties and micropores exhibited negligible water adsorption (108.54 mgg−1) at relatively low pressures (P/P0~0.3) but showed a rapid increase in water adsorption ability (475.7 mgg−1) at relative pressures of about 0.6. A comparison with the isotherm model indicated that the results were consistent with the theories, which include site filling at low relative pressure and pore filling at high relative pressure. In particular, the Do–Do model specialized for type 5 showed excellent agreement.

MOF- or ZIF-derived carbon (MDC/ZDC) has attracted significant attention especially in catalysis applications, because well-dispersed metal or oxide nanoparticles over the MDC/ZDC matrix with retained MOF/ZIF porosity can be obtained with direct pyrolysis. Although it seems to be a facile approach, pyrolysis parameters could significantly alter the MDC/ZDC properties. However, an in-depth study on the pyrolytic factors has not been discussed. Herein, we manipulated ZIF structure, pyrolytic atmosphere, temperature, incubation time, and ramping/cooling rates for ZDC structural analyses. Compared to pure ZIF-67 derived carbon with only Co metal nanoparticles, it was observed that the carbonization process in core-shell ZIF-8@ZIF-67 (Z8@Z67) initiated the interdiffusion of reduced metal ions at the core-shell interface, which triggered the unique Zn-Co alloying behavior forming Zn 3 Co when they were in close proximity. The resultant intermetallic Zn 3 Co compound is unstable and has never been experimentally observed. By employing the in situ powder X-ray diffraction (PXRD) technique, we observed the fast-heating plus cooling process arrested or circumvented the phase segregation, and kept the metastable intermetallic Zn 3 Co. For the first time, we report a method to maintain it at ambient conditions, protected by the porous MOF derivative from ZIF pyrolysis. [Display omitted] • Well-dispersed Co nanoparticles is observed during Zn-Co core-shell ZIF pyrolysis. • Metastable phase Zn 3 Co is formed and preserved after core-shell ZIF pyrolysis. • The existence of Zn 3 Co can be controlled by ZIF pyrolytic ramping/quenching rates. [ABSTRACT FROM AUTHOR]