Domino Effect of Catalysis: Coherence between Reaction Network and Catalyst Restructuring Accelerating Surface Carburization for CO₂ Hydrogenation

Dynamic carburization is a common and important phenomenon in many industrial reactions. Finding the critical factor governing this process is significant for catalyst optimization, which is complicated due to the coherence between catalyst dynamics and reaction dynamics. In this work, we manipulate the <i>in situ</i> formation of fast carburization on the Pd-FeO_<i>x</i> surface by revealing a domino effect between the reaction network and catalyst restructuring during long-term CO₂ hydrogenation reaction. We prepared catalysts of three sizes (5Pd-FeO_<i>x</i>, 0.5Pd-FeO_<i>x</i>, 0.05Pd-FeO_<i>x</i>) and found that the large size of Pd NP (5Pd-FeO_<i>x</i>) induces the reactive metal-support interaction, following the <i>in situ</i> Pd₃Fe formation, the reaction route change, the fast surface carburization (Fe₅C₂), and finally the superior catalytic performance. Among these changes, we identify that <i>in situ</i> alloying instead of the apparent size difference is crucial for the formation of the active Fe₅C₂ phase. As a proof of concept, we further design a presynthesized Pd₃Fe alloy on FeO_<i>x</i> and find an enhanced activity with reduced Pd loading by controlled fast carburization. This work not only demonstrates the controllability of dynamic carburization but also presents a benchmark of optimizing catalysts through the comprehensive understanding of <i>in situ</i> catalyst changes.