Selective Fischer–Tropsch synthesis for jet fuel production over Y3+ modified Co/H-β catalysts
Co/Y-β-x catalysts were prepared by Y3+ multiple ion-exchange with H-β zeolites followed by wet-impregnation of cobalt. With Y promotion, the activity of CO hydrogenation and selectivity of jet fuel range hydrocarbons were improved in the selective Fischer–Tropsch reaction. This could be attributed to the reduction of the average crystallite size of Co, the increase of its active surface area, caused by the improvement of the dispersion and reducibility of Co3O4, and the adjustment of acid sites in the catalysts. However, an excessive addition of Y3+ led to the increase of Brønsted acidity, deriving from the hydrolysis of Y3+ adsorbed on the surface of H-β zeolite. Therefore, the Co/Y-β-3 catalyst with an appropriate proportion of Y achieved an optimal JFRH selectivity of 41.2% with a yield of 34.5%.