FTIR study of CO and N2 adsorption on [Ge]FAU zeolites in their Na- and H-forms

摘要: Abstract A [Ge]FAU zeolite sample (2.36 wt. % Ge) was synthesized by a new approach comprising utilization of mother liquids instead seeds and characterized FTIR spectroscopy adsorbed CO N 2 as probe molecules. Ge-free with similar Al concentration also prepared studied for comparison. The background spectra the H-[Ge]FAU do not give indication presence Ge(OH)Al bridging hydroxyls. However, incorporation Ge affects properties Thus, CO-induced shifts bands due to HF hydroxyls are larger indicating higher protonic acidity this material. same results obtained . Adsorption on NaFAU shows that accessible Na + sites uniform low coordinated: At high coverage (N ) geminal species observed converted into –N adducts at lower coverage. Similar adsorption, i.e. conversion between (CO) –CO species. phenomena were detected Na-[Ge]FAU sample. in case, two different clearly detected. Because adsorption ions believed be located S II positions, suggest some affected second coordination sphere. This is consistent fact that, contrary proton (bonded one oxygen), cations coordinated three framework oxygens.