Sustainable Synthesis of MCM-22 Zeolite as a Catalytic Platform for Propane Dehydrogenation

The significant volume of solvent required for the hydrothermal synthesis of zeolites remains the primary hurdle impeding industrial applications. With the benefits of reduced manufacturing costs, safety, and energy savings, reducing the use of solvents is one of the significant sought-after objectives. In this study, borosilicate zeolite B-MCM-22 is successfully obtained using a solvent-free synthesis method. The as-synthesized sample exhibits good long-range order, high crystallinity, and high silica utilization (ca. 95%). Furthermore, the B-MCM-22 precursor serves as a platform for introducing Co active sites via deboronization and impregnation processes. The resulting Co-MCM-22-DB catalyst provides a propylene selectivity of >90% with an initial propane conversion of 38% in the propane dehydrogenation reaction and shows a higher initial catalytic performance than the Co/ITQ-1 catalyst. The essential interplay between the metal-support interaction and catalytic performance is demonstrated by ultraviolet-visible (UV-vis), H₂-TPR, and catalytic assessments, further elucidating that Co²⁺ species are the active sites for propane to propylene conversion. We anticipate that B-MCM-22 will be a versatile and ideal platform for catalyst design through structural manipulation.