Ionothermal syntheses and characterizations of cobalt-substituted extra-large pore aluminophosphate molecular sieves with -CLO topology

• Cobalt aluminophosphates with -CLO structure were ionothermally synthesized.
• The gel composition and crystallization time affected the phase selectivity greatly.
• UV–Vis spectra of CoDNL-1 samples revealed four-coordinated Co(II) in the framework.

Cobalt-substituted aluminophosphate molecular sieves with -CLO structure (denoted as CoDNL-1) have been synthesized in the ionic liquid 1-ethyl-3-methylimidazolium bromide with 1,6-hexanediamine as the cooperative structure-directing agent (co-SDA). The influence of various synthesis parameters (e.g. gel compositions and crystallization time) on the synthesis of CoDNL-1 has been investigated in detail. The products have been characterized by powder XRD, SEM, XRF, TG, N2-adsorption, diffuse reflectance UV–Vis spectroscopy, 27Al and 31P MAS NMR spectroscopy and in situ XRD. Powder XRD, TG, chemical analysis and NMR indicate the incorporation of Co2+ ions into the -CLO framework. UV–Vis spectra reveal that Co2+ ions are present in tetrahedral sites of the -CLO framework. In situ XRD analyses show that CoDNL-1 possesses good thermal stability and the cobalt content in the framework influences the thermal stability of CoDNL-1.

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