Thermosensitive structural changes and adsorption properties of zeolitic imidazolate framework-8 (ZIF-8)

Taehee Lee, Hyungmin Kim, Woosuk Cho, Doug Young Han, Muhammad Ridwan, Chang Won Yoon, Jong Suk Lee, Nakwon Choi, Kyoung Su Ha, Alex C K Yip, Jungkyu Choi

Research output: Contribution to journalArticlepeer-review

11 Citations (Scopus)

Abstract

We compared four types of ZIF-8 with varying sizes and shapes to determine their thermal-structural stability and derive appropriate thermal activation conditions and correlation between structural characteristics and adsorption properties. Under air, the ZIF-8 phase for all the samples was converted completely into the zinc oxide phase above ∼300°C, though thermalgravimetric analysis (TGA) indicated that the original structure was stable to ∼300-350°C. Longer exposures (∼30 d) suggested that thermal activation at ∼200°C was appropriate for the removal of guest and/or solvent molecules under air without structural damage. Despite no noticeable change in X-ray diffraction (XRD) patterns after activation at 250°C under air, the resulting BET surface areas and CO<inf>2</inf> adsorption amounts (at 1 bar and 30°C) of ZIF-8s were reduced to ∼44-54 and ∼72-87%, respectively, as compared to those of appropriately activated ZIF-8s. It appears that after the activation at 250°C under air, some Zn and N atoms were dissociated and converted to ZnOH and NOH, respectively, causing the partial structural damage of ZIF-8s.

Original languageEnglish
Pages (from-to)8226-8237
Number of pages12
JournalJournal of Physical Chemistry C
Volume119
Issue number15
DOIs
Publication statusPublished - 2015 Apr 16

ASJC Scopus subject areas

  • Physical and Theoretical Chemistry
  • Electronic, Optical and Magnetic Materials
  • Surfaces, Coatings and Films
  • Energy(all)

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