| Summary: | The catalytic hydrogenation of CO<sub>2</sub> to light olefins (C<sub>2</sub>–C<sub>4</sub>) is among the most practical approaches to CO<sub>2</sub> utilization as an essential industrial feedstock. To achieve a highly dispersed active site and enhance the reactivity of the reverse water–gas shift (RWGS) reaction, ABO<sub>3</sub>-type perovskite catalysts Sr<sub>1-x</sub>K<sub>x</sub>FeO<sub>3</sub> with favorable thermal stability and redox activity are reported in this work. The role of K-substitution in the structure–performance relationship of the catalysts was investigated. It indicated that K-substitution expedited the oxygen-releasing process of the SrFeO<sub>3</sub> and facilitated the synchronous formation of active-phase Fe<sub>3</sub>O<sub>4</sub> for the reverse water–gas shift (RWGS) reaction and Fe<sub>5</sub>C<sub>2</sub> for the Fischer–Tropsch synthesis (FTS). At the optimal substitution amount, the conversion of CO<sub>2</sub> and the selectivity of light olefins achieved 30.82% and 29.61%, respectively. Moreover, the selectivity of CO was up to 45.57% even when H<sub>2</sub>/CO<sub>2</sub>=4 due to CO<sub>2</sub>-splitting reactions over the reduced Sr<sub>2</sub>Fe<sub>2</sub>O<sub>5</sub>. In addition, the reversibility of perovskite catalysts ensured the high dispersion of the active-phase Fe<sub>3</sub>O<sub>4</sub> and Fe<sub>5</sub>C<sub>2</sub> in the SrCO<sub>3</sub> phase. As the rate-determining step of the CO<sub>2</sub> hydrogenation reaction to light olefins over Sr<sub>1-x</sub>K<sub>x</sub>FeO<sub>3</sub> perovskite catalysts, FTS should be further tailored by partial substitution of the B site. In sum, the perovskite-derived catalyst investigated in this work provided a new idea for the rational design of a catalyst for CO<sub>2</sub> hydrogenation to produce light olefins.
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