Ionothermal synthesis and characterization of CoAPO-34 molecular sieve

Abstract

The cobalt-doped aluminophosphate molecular sieve, CoAPO-34 (with the chabazite-type topology) was prepared under ionothermal conditions using 1-ethyl-3-methylimidazolium bromide (EMIMBr) ionic liquid in presence of 1,6-hexanediamine (HDA). The HDA is not incorporated in CoAPO-34, but is required to mediate the availability of Co2+ during the synthesis. The material was characterized using powder X-ray diffraction (PXRD), thermogravimetric analysis (TGA) and solid-state NMR spectroscopy. Wideline 31P NMR spectroscopy showed broad signals (∼5000–10000 ppm wide), confirming that paramagnetic cobalt ions are successfully incorporated within the framework of the materials.