Interfacing with Carbonaceous Potassium Promoters Boosts Catalytic CO2Hydrogenation of Iron

Directly converting carbon dioxide into high-valued olefins (ethylene, propylene, and linear α-olefins) with regenerative hydrogen could be a way of reducing CO2 emissions and replacing fossil fuels. However, precise control of C-O activation and subsequent C-C coupling toward those olefins remain a challenge, due to the unclear catalytic mechanism on active sites and surrounding promoters. Herein, we demonstrate that the carbonaceous series K-promoters from K2CO3, CH3COOK, KHCO3, and KOH can induce Fe/C catalysts to form a more active and distinct Fe5C2-K2CO3 interface in nanoscale via CO2 hydrogenation, which boosts the production of high-valued olefins by facilitating electron transfer from potassium to iron species. A high olefin selectivity of near 75% in hydrocarbons is realized at a conversion of more than 32%. The maximum yield of high-valued olefins reaches up to 20.1%, which is the record-breaking highest value among all Fe based CO2 hydrogenation in the literature. More interestingly, the appropriate proximity between carbonaceous K-promoters and Fe/C catalyst endow the catalytic system with an outstanding high-valued olefin yield and high catalytic stability. These findings enrich the chemistry of CO2 conversion and provide a strategy to design highly selective catalysts for high-valued chemicals.