Porous Graphene-Confined Fe–K as Highly Efficient Catalyst for CO<sub>2</sub> Direct Hydrogenation to Light Olefins

We devised iron-based catalysts with honeycomb-structured graphene (HSG) as the support and potassium as the promoter for CO<sub>2</sub> direct hydrogenation to light olefins (CO<sub>2</sub>–FTO). Over the optimal FeK1.5/HSG catalyst, the iron time yield of light olefins amounted to 73 μmol<sub>CO2</sub> g<sub>Fe</sub><sup>–1</sup> s<sup>–1</sup> with high selectivity of 59%. No obvious deactivation occurred within 120 h on stream. The excellent catalytic performance is attributed to the confinement effect of the porous HSG on the sintering of the active sites and the promotion effect of potassium on the activation of inert CO<sub>2</sub> and the formation of iron carbide active for CO<sub>2</sub>–FTO.