Details

Autor(en) / Beteiligte

• Hou, Buwei
• Wu, Jie

Titel

Halloysite nanotubes (HNTs)@ZIF-67 composites-a new type of heterogeneous catalyst for the Knoevenagel condensation reaction

Ist Teil von

• Dalton transactions : an international journal of inorganic chemistry, 2020-12, Vol.49 (48), p.17621-17628

Ort / Verlag

England: Royal Society of Chemistry

Erscheinungsjahr

2020

Quelle

Alma/SFX Local Collection

Beschreibungen/Notizen

• Composite materials based on metal-organic frameworks (MOFs) have shown outstanding performance due to their high porosity, molecular-level characterization, and structural and functional tunability. In this article, we develop a new type of composite material-HNTs@ZIF-67-by the in situ growth of ZIF-67 nanoparticles (NPs) on halloysite nanotubes (HNTs), which were characterized by SEM, TEM, PXRD, FT-IR, TGA, XPS and N 2 adsorption-desorption isotherms. The results clearly indicate that HNTs were wrapped in the ZIF-67 shell with a thickness of 50 nm which is much smaller than the 500 nm size of the as-synthesized ZIF-67. The nano-sized HNTs@ZIF-67 can effectively catalyze the Knoevenagel condensation reaction of larger conjugated/heterocyclic aromatic formaldehydes with malononitrile. The catalytic activities with >99% yields for the reaction of 4-pyridinecarboxaldehyde with malononitrile were maintained even after three cycles, and the composite still retained the original structure and morphology. Halloysite nanotubes (HNTs) are encapsulated in 50 nm thick shells of ZIF-67, producing novel nano-sized composites HNTs@ZIF-67.