Synthesis of Co-substituted Zeolites in the presence of cobalt complex with EDMA

In the presence of a monovalent cobalt complex with EDMA, we sought to synthesize zeolite from aluminosilicate gels in hydrothermal conditions. Using these gels, we obtained three kinds of zeolites, i.e., of the MOR-, MFI-, and ANA-type. We characterized in detail the obtained MOR- and ANA-type zeolite by means of thermal analysis, UV–Vis-IR spectrometry and TOF-SIMS measurement. The results showed that cobalt atoms are located in the MOR- and ANA-type framework (namely through Co atom substitution), and not in the micropores as a complex. On the other hand, a small number of cobalt atoms are distributed in a micropore of the MFI-type zeolite as a cation.

Graphical abstractThe Co-substituted MOR- and ANA-type zeolites were synthesized using aluminosilicate gels with a monovalent Co-EDTA complex. In the diffuse optical absorption spectra, characteristic absorption bands in the range of 450–720 nm unrelated to the framework structure or the hydration conditions were observed. These absorptions are derived from the cobalt atom incorporated into the T site.Figure optionsDownload full-size imageDownload as PowerPoint slideResearch highlights► Co-substituted zeolites were synthesized in the presence of Co(EDMA)2 complex. ► Sample colors of Co-substituted zeolites were blue before and after calcination. ► Co(EDMA)2 complex compounds do not play a role of the template in the synthesis. ► Co atom substitution was investigated by UV–Vis-IR and TOF-SIMS measurements.