Tandem Pt/TiO2 and Fe3C catalysts for direct transformation of CO2 to light hydrocarbons under high space velocity

Abstract

CO₂ hydrogenation to hydrocarbons under high space velocity is crucial for industrial applications, but traditional Fe-based catalysts often suffer from the low activity and poor stability. Herein, we report a new tandem catalyst system combining Pt/TiO₂ catalysts with Fe₃C catalysts for the direct conversion of CO₂ into C₂-C₄ hydrocarbons under high space velocity. The Pt/TiO₂ component promotes *CO intermediate production with an enhanced Reverse Water-Gas Shift (RWGS) reaction efficiency, providing a highly reactive species for the Fe₃C catalyst to achieve Fischer-Tropsch synthesis (FTS). By maximizing the contact interface between the Pt/TiO₂ and Fe-based components through a granule mixing configuration, we achieve significant enhancements in both CO₂ conversion rate (24.0 %) and C₂-C₄ hydrocarbons selectivity (51.1 %) under the gaseous hourly space velocity (GHSV) of 100000 mL g_cat⁻¹h⁻¹. Besides, excellent stability is achieved by the tandem catalysts with continuous catalysis for up to 80 h without significant decrease in activity. Through modulation of the reduction states of iron oxide, we effectively tune the composition of Fe-based catalyst, thereby tailoring the product distribution. Through this work, we not only offer a promising avenue for reducing CO₂ for efficient CO₂ utilization but also highlight the importance of catalyst design in advancing sustainable chemical synthesis.