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

•Hierarchical zeolite Y is prepared by the sequential leaching process.•The mesopore volume increases after the sequential treatment.•Low methane selectivity and excellent high isoparaffin selectivity are achieved.•Better catalytic performance is attributed to the combine acidity and mesoporisity.

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 C5–11 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.

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