Enhancing the synergism of Fe3O4 and Fe5C2 to improve the process of CO2 hydrogenation to olefines

CO 2 hydrogenation to olefines is a feasible carbon capture and utilization (CCU) route. The process includes sequential reactions of reverse water gas shift (RWGS) reaction and Fischer-Tropsch synthesis (FTS) reaction. The acceleration of FTS is crucial to improve the olefines yield. A microemulsion anti-solvent extraction (MAE) method was proposed to prepare Fe-based catalyst on the support of Al 2 O 3 . Ethanol solution of Fe(NO 3 ) 3 was encapsulated in microdroplets, and then loaded on Al 2 O 3 by the extraction of ethanol from the microdroplets to isooctane phase. The average size of micro droplets was 7.5 nm. After calcination , the particle size of Fe 2 O 3 was 6 nm. After carburization with CO, the interface formed between Fe 3 O 4 and Fe 5 C 2 was restricted in a narrow space with a mean size of 12 nm. Through TEM-Mapping, XRD , XPS and TPC characterization, the distribution uniformity of Fe and the neighboring degree of Fe 3 O 4 and Fe 5 C 2 on the as-prepared catalyst MAE-Fe 1 K 1 was improved effectively. An enhanced synergistic effect between Fe 3 O 4 and Fe 5 C 2 was obtained. The catalytic performance evaluation results showed that yield of C 2 -C 4 olefins reached 0.063 mmol·gFe −1 ·s −1 after 12 h of reaction. It exhibited better catalytic performance than most catalysts reported in the literatures. The results showed that the proposed microemulsion anti-solvent extraction strategy is an effective method to prepare Fe-based catalyst for CO 2 -FTO reaction with an excellent catalytic performance.