Controlling ZIF-67 crystals formation through various cobalt sources in aqueous solution

• Published in: Journal of solid state chemistry 2016-03, Vol.235, p.107-112
• Main Authors: Guo, Xiangli, Xing, Tiantian, Lou, Yongbing, Chen, Jinxi
• Format: Article
• Language: English
• Subjects: AGGLOMERATION; AQUEOUS SOLUTIONS; Aqueous synthesis; COBALT; COBALT CHLORIDES; COBALT IONS; COBALT NITRATES; COBALT SULFATES; COMPARATIVE EVALUATIONS; CONTROL; Crystal structure; CRYSTALS; INORGANIC, ORGANIC, PHYSICAL AND ANALYTICAL CHEMISTRY; MATERIALS SCIENCE; Morphology; NITROGEN OXIDES; PARTICLE SIZE; PARTICLES; REACTIVITY; SALTS; SYNTHESIS; Various cobalt salts; ZEOLITES; Zeolitic imidazolate frameworks ZIF-67
• ISSN: 0022-4596; 1095-726X
• DOI: 10.1016/j.jssc.2015.12.021

Zeolitic imidazolate frameworks ZIF-67 were prepared under hydrothermal (120°C) and non-hydrothermal (room temperature) from various cobalt sources and 2-methylimidazolate (Hmim) in aqueous solution within 30min. The particle size and morphology were found to be related to the reactivity of the cobalt salt, Hmim/Co2+ molar ratios and experimental condition. Using Co(NO3)2 as cobalt source, small-sized ZIF-67 crystals with agglomeration were formed. For CoCl2, small-sized rhombic dodecahedron were obtained. While large-sized crystals of rhombic dodecahedron structure were obtained from CoSO4 and Co(OAc)2. Under hydrothermal condition, the size of ZIF-67 crystals tended to be more uniform and the morphology were more regular comparing to non-hydrothermal condition. This study provides a simple way to control the size and morphology of ZIF-67 crystals prepared in aqueous solution. Zeolitic imidazolate frameworks ZIF-67 were prepared under hydrothermal (120°C) and non-hydrothermal (room temperature) from four different cobalt sources (Co(NO3)2, CoCl2, CoSO4 and Co(OAc)2) in aqueous solution within 30min. The particle size and morphology were found to be related to the reactivity of the cobalt salt, Hmim/Co2+ molar ratios and experimental condition. [Display omitted] •The particle size and morphology were determined by the reactivity of cobalt salt.•ZIF-67 could be prepared from CoSO4 and Co(OAc)2 at Hmim/Co2+ molar ratio of 10.•Uniform and regular particles were obtained under hydrothermal condition.