Catalytic conversion of CO2-rich syngas to high-quality gasoline hydrocarbons over In2O3-ZrO2/SAPO-11 catalysts
The conversion of CO2 into gasoline-range hydrocarbons represents a sustainable pathway to achieve deep decarbonization in the transportation sector. Nevertheless, the traditional Fischer-Tropsch synthesis (FTS) suffers from a broad product distribution, which restricts the achievable selectivity toward C5−C11 gasoline-range hydrocarbons to roughly 45%. This study presents the development of a bifunctional catalyst that integrates In2O3/ZrO2 metal oxides with SAPO-11 molecular sieves, aiming at efficiently converting CO2/CO mixtures into C5−C11 gasoline hydrocarbons. Catalysts with varying In/Zr ratios were prepared via co-precipitation. By employing a COx (CO/CO2) co-feeding strategy (CO/COx = 0.5), the formation of by-product CO was significantly suppressed, thereby enabling the selectivity for gasoline hydrocarbons to exceed the maximum predicted by the Anderson-Schulz-Flory (ASF) model. Notably, under identical reaction conditions, the In2Zr1Ox/SAPO-11 catalyst exhibited higher performance compared with In2O3/SAPO-11 and ZrO2/SAPO-11. The COx conversion was elevated by 1.7% and 0.2%, while the selectivity toward C5–C11 hydrocarbons was enhanced by 8.0% and 16.0%, respectively. Furthermore, the In2Zr1Ox/SAPO-11 catalyst delivered a single-pass performance of 24% COx conversion and 68% selectivity for C5−C11 hydrocarbons at 380 °C, 3 MPa and a gas hourly space velocity (GHSV) of 2400 mL/(min·g). Within this product distribution, isoparaffins accounted for 32.6% of the total components, corresponding to an isoparaffin/neoparaffin ratio of 12.3. After 150 h of stability testing, the catalyst maintained a single-pass COx conversion of 23% and a C5−C11 selectivity of ~65%, demonstrating excellent catalytic activity and promising potential for industrial application.