Preparation of ZrO2 modified Al2O3 nano-sheets supported cobalt catalyst and its performance in Fischer-Tropsch synthesis

Al2O3 nano-sheet (Al2O3-CN) was synthesized under hydrothermal condition. The cobalt-based catalyst of 20% (mass fraction) was prepared by impregnation method and applied to Fischer-Tropsch synthesis. The Al2O3-CN (226 m2/g) and commercial alumina (Al2O3-C, 249 m2/g) have similar specific surface area, but Al2O3-CN has more narrow pore size distribution. Compared with Co/Al2O3-C catalyst, Co/Al2O3-CN catalyst showed higher reduction degree and more uniform cobalt particle size distribution after impregnation. Thus, Co/Al2O3-CN catalyst exhibited higher CO conversion and lower methane selectivity. In order to further improve the catalytic performance of Co/Al2O3-CN, Al2O3-CN was modified with ZrO2. The characterization results showed that with the increase of ZrO2, the specific surface of Al2O3-CN did not change significantly, and the pore volume and pore diameter increased. The cobalt particle size decreased and the number of active sites increased. Under the same reaction conditions, the CO conversion rate of catalysts modifield by ZrO2 was further improved and selectivity of methane was decreased.