Dynamic Phase Transition of Iron Oxycarbide Facilitated by Pt Nanoparticles for Promoting the Reverse Water Gas Shift Reaction

The catalytic activation of CO2 is a crucial process in CO2 recycling for both fundamental research and industrial applications. Fe-based catalysts have been demonstrated to be highly active for the reverse water gas shift (RWGS) reaction. However, the structural complexity and dynamic reduction/oxidation/carburization of iron-based catalysts mean that it is challenging to understand the mechanism of these catalysts and further improve their reaction activity. Herein, we report a highly efficient Pt/Fe3O4 catalyst for the RWGS reaction, in which the content of Pt is only 0.017 wt %. The CO2 conversion rate reaches 46.9 x 10(-5) mol(CO2)(g(cat) s) with a CO selectivity of up to 99.7% at reaction conditions of 500 degrees C and atmospheric pressure. Structure-performance investigations reveal that the reduction process of Fe-based supports can be enhanced by the in situ formation of Pt nanoparticles, which significantly promote the dynamic phase transition of Fe3O4 to Fe3C via carburization and thus considerably improve CO2 activation. The synergistic interaction of Pt with Fe-oxycarbide improves catalytic activity and ensures long-term catalytic stability. This simple strategy by improving the reduction process of Fe-based catalysts to promote carburization provides an alternative way to manipulate the activity and selectivity of Fe-based catalysts in CO2 hydrogenation.