Synthesis and characterization of Fe₂O₃/HY from kaolin as catalysts in the partial oxidation reaction of methane to methanol

Methane is one of the most useful gas that can be used directly as fuel. Nevertheless, toxic gas emission after used is still at high number while its efficiency is still very low. On the other hand, methane can be converted to methanol via partial oxidation reaction for further use. In this study, HY zeolite, synthesized from kaolin impregnated with iron (III) oxide, were used as catalysts in methane partial oxidation reaction. Two types of HY zeolite were synthesized with or without additional cetyltrimethylammonium bromide as secondary template, which were labeled as hierarchical and microporous Y zeolite, respectively. Then, both zeolites were modified via cation exchange with NH₄⁺ and impregnated with iron (III) oxide which produced Fe₂O₃/HY after calcined at 550 °C. As comparison, Y zeolites were also prepared using synthetic precursors such as colloidal silica and sodium aluminate. All materials then were analyzed with X-Ray Diffraction (XRD), Scanning Electron Microscope (SEM), and infrared spectroscopy (FTIR). The XRD analysis showed that both as-synthesized Y zeolites had similar pattern to standard zeolite Y. The FTIR analysis also showed that both zeolite have all peaks attributed to functional groups in Y zeolite. Application test was carried out on each catalyst towards the conversion of methane to methanol by using methane pro analysis as the source of methane and reacted in atmospheric fixed batch reactor with the ratio of CH₄ and N₂ (0.5 % O₂) is 0.075:2 Bar. Reaction is performed at 150 °C for 120 min. Products of each reaction was analyzed with GC-FID to know the percentage of methanol yield. The results showed that the % yield of methanol was similar for all catalysts, in which Fe₂O₃/microporous HY-syn gives as high as 19.11 %, then 18.73 % from Fe₂O₃/hierarchical HY-nat, 18.60 % from Fe₂O₃/hierarchical HY-syn, and 18.46 % from Fe₂O₃/microporous HY-nat.