Improved olefin selectivity during CO hydrogenation on hydrophilic Fe/HAP catalysts

The hydrophilic/hydrophobic properties of catalysts greatly influence product distribution by tuning the sec-ondary reactions during Fischer-Tropsch synthesis. Studies have confirmed that hydrophilic modification can inhibit secondary reactions. Herein, hydroxyapatite (HAP)-supported Fe catalysts (Fe/HAP) were prepared using an impregnation method. The effect of the catalyst surface properties on the product distribution in CO hy-drogenation was studied. The surface hydroxyl groups on Fe/HAP promoted the growth of carbon chains and improved olefin selectivity. The addition of Na as a promoter to Fe/HAP suppressed the formation of undesirable CH4, further improving the selectivity for light olefins and C5+ hydrocarbons. Compared with Fe2O3, Fe/HAP showed lower CH4 selectivity (15%) and higher C5+ selectivity (45%). Meanwhile, the Fe/HAP-Na catalysts with a higher selectivity of light olefins (with an O/P ratio reaching 4.51).

Automated summary

The hydrophilic/hydrophobic properties of catalysts greatly affect product distribution in Fischer-Tropsch synthesis by modulating secondary reactions. It has been found that hydrophilic modification can inhibit secondary reactions. In this study, Fe catalysts supported on hydroxyapatite (HAP) were prepared using an impregnation method. The effect of catalyst surface properties on CO hydrogenation product distribution was investigated. The surface hydroxyl groups on Fe/HAP promoted carbon chain growth and improved olefin selectivity. The addition of Na promoter suppressed the formation of undesirable CH4, further enhancing the selectivity for light olefins and C5+ hydrocarbons. Fe/HAP exhibited lower CH4 selectivity (15%) and higher C5+ selectivity (45%) compared to Fe2O3. Meanwhile, Fe/HAP-Na catalysts achieved a higher selectivity of light olefins (with an O/P ratio of 4.51).