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چکیده
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A series of Ni-Co/Al2O3-MgO-ZrO2 nanocatalysts with various ZrO2 loadings were prepared via sol-gel method and used in CH4/CO2 reforming. The nanocatalysts were characterised using XRD, FESEM, FTIR and BET analysis. The XRD patterns represented that by adding ZrO2 to Ni-Co/Al2O3-MgO, the crystallinity declined and amorphous behaviour became intensified. According to the FESEM images, addition of 5 wt% zirconia led to smaller particles size and improved particles size distribution. The texture of the catalyst or BET surface area was affected by adding zirconia, which is caused by covering of support pores by ZrO2 and formation of ZrO2-Al2O3 solid solution. All of the nanocatalysts exhibited acceptable catalytic performance and remarkably, deactivation was not observed throughout the 1,440 min and at 850°C. Among the prepared nanocatalysts, the sample which contained 5 wt% ZrO2 exhibited the best catalytic performance since it possesses higher reactants conversion and superior products yield and production of synthesis gas with ratio close to unity throughout the 1,440 min and at 850°C. Generally, based on the superior properties evidenced by characterisations techniques and improved catalytic performance of nanocatalyst with lower zirconia content, 5 wt% ZrO2 was the optimal amount of stabilising the Ni-Co/Al2O3-MgO for CH4/CO2 reforming.
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