Pure-phase ε/ε' iron carbide catalyst for fischer-tropsch synthesis reaction, preparation method therefor and fischer-tropsch synthesis method

A pure-phase e/e' iron carbide catalyst for Fischer-Tropsch synthesis reaction, a preparation method therefor and a Fischer-Tropsch synthesis method, the preparation method comprising the following steps: (1) purifying the surfaces of nanometer iron powder or a nano-powder iron compound of the nanometer iron powder obtained by means of in-situ reduction and H2 at 250-510°C; (2) performing pretreatment on the material obtained in step (1) together with H2 and CO at 80-180°C, the molar ratio of H2 to CO being 1.2-2.8: 1; and (3) preparing a carbide by using the material obtained in step (2) along with H2 and CO at 180-280°C, the molar ratio of the H2 to CO being 1.0-3.0: 1. The described preparation method has the advantages of raw materials that are easy to obtain and simple operation steps and may prepare a 100% pure-phase e/e' iron carbide catalyst, which has low CO2 and CH4 selectivity and highly effective product selectivity.