Highly selective iron-based Fischer–Tropsch catalysts activated by CO2-containing syngas

AbstractFischer–Tropsch synthesis (FTS) was carried out over precipitated iron-based catalysts activated by syngas (H2+CO) with different amounts of CO2 (0%, 20%, 33%, and 50%). The activation using CO2-containing syngas significantly suppressed the production of undesired products, CH4 and C2–C4 hydrocarbons, but facilitated the production of valuable products, C5+ hydrocarbons. In particular, in the case of C19+ hydrocarbons, the target products of low-temperature FTS (⩽280°C), both selectivity and productivity showed a great increase with an increased inlet CO2 content during activation. We attribute the advantageous performance of the catalysts activated by CO2-containing syngas to the improvement in the effective performance of active iron carbides, possibly induced by an increased ratio of ε′-carbide (Fe2.2C) to χ-carbide (Fe2.5C) and a decreased fraction of inactive bulk carbons