Hierarchical zeolite y supported cobalt bifunctional catalyst for facilely tuning the product distribution of Fischer-Tropsch synthesis

A two-step method consisting of acid leaching and base leaching was developed and applied to create hierarchical pores on a general microporous Y zeolite. Characterization with BET and TEM on the texture, morphology and structure of the prepared hierarchical Y zeolite confirmed the co-existence of mesopores with zeolitic walls. The analysis results showed that the mesopore surface area and pore volume of the hierarchical zeolite Y (Y-ABx, A: acid leaching, B: base leaching, "x" represents for base leaching time) increased with increasing the base leaching time. The hierarchical zeolite Y supported Co as catalysts were employed to catalyze the hydrogenation of carbon monoxide to form hydrocarbons through Fischer-Tropsch synthesis (FTS) reaction. The CO conversion and C_5-11 selectivity on Co/Y-ABx catalysts increased significantly compared with those on the pristine Y supported Co catalyst. The isoparaffin selectivity of Co/Y-AB4 catalyst reached up to 52.3% and middle hydrocarbons became the main FTS products due to the optimized hydrocracking and isomerization function afforded by the hierarchical zeolite Y with the strong Brønsted acid/Lewis acid (B/L) ratio and textural property.