Enhanced conversion of syngas to high-quality gasoline hydrocarbons over ZnZrOx coupled SAPO-11 nanosheets bifunctional catalyst

Syngas is a key precursor for synthesizing gasoline (C 5 -C 11 ) hydrocarbons, offering an efficient route for utilizing non-petroleum carbon sources. However, the conventional Fischer-Tropsch synthesis (FTS) process faces a constraint with a maximum 45% selectivity for C 5 -C 11 , attributed to the Anderson-Schultz-Flory (ASF) distribution. Herein, bifunctional catalysts comprising ZnZrO x with different Zr/Zn ratios along with SAPO-11 zeolite sieves featuring varied morphologies like nanosheets (SA-A), petals (SA-B), and spheres (SA-C) have been effectively formulated and employed for the syngas-to-gasoline hydrocarbons (STG) reaction. Notably, the selectivity toward C 5 -C 11 far exceeded the ASF limits. Under identical reaction parameters, the Zn 1 Zr 4 O x /SA-A catalyst demonstrated notable enhancements of 6.6% and 26.2% in CO conversion, along with 4.6% and 7.6% increases in C 5 -C 11 selectivity, as compared to that of Zn 1 Zr 4 O x /SA-B and Zn 1 Zr 4 O x /SA-C catalysts, respectively. Furthermore, under the ideal conditions (380 °C, 4.5 MPa and gas hourly space velocity (GHSV) of 2400 mL min −1  g −1 ), Zn 1 Zr 4 O x /SA-A exhibited an exceptional C 5 -C 11 selectivity of 69.8% (CO 2 -free) alongside a single-pass CO conversion of 30.4%. Impressively, isoparaffin constituted 39.2% of the total composition , with the iso/n-paraffin ratio reaching 11.8. Even after 100 h, the catalyst maintained its remarkable catalytic activity , with the CO conversion and C 5 -C 11 selectivity maintaining levels of 27.5% and 66.85%, respectively.