The synthesis of high cobalt-containing CoAPO-34

High cobalt-containing CoAPO-34 has been synthesized using tetraethylammonium hydroxide (TEAOH) and [(CH3CH2)(4)N]2CoCl4 as a cobalt source and additional templating agent. Pure CoAPO-34 was obtained by replacing up to 0.4 mol fraction of the aluminum by cobalt in the reaction gel at varying template concentrations. The crystallization of CoAPO-34 with impurities occurs at 0.5 mol fraction substitution and above. Analysis and characterization of the products by X-ray diffraction (XRD), X-ray fluorescence (XFR), infrared (i.r.) spectroscopy, thermogravimetric analysis (t.g.a.), and Scanning Electron Microscopy (SEM) is described. X-ray diffraction has shown an increase in d-spacings relative to AIPO(4)-34, and chemical analysis has shown samples containing around 30% framework cobalt. The unit cell, found to be hexagonal in symmetry, increases in volume between the 0.2 and 0.4 mot fraction substitution levels, but little change is observed in unit cell size between the 0.4 and 0.5 mol fraction substitution level. This has been explained in terms of changing bond lengths and angles with increasing framework substitution of cobalt. Infrared spectroscopy has shown a decrease in the frequencies of the asymmetric and symmetric stretching regions and in the T-O bending region with increasing cobalt content.