(561d) Activity Descriptor Identification of Edge-Hosted Fe-N3 Sites for the Catalytic Transfer Hydrogenation

The selective transformation of biomass-derived platform molecules into value-added fuels and chemicals plays an essential role in biomass upgrading ^[1]. M-N-C catalysts have attracted increasing attention due to their theoretical 100% atom efficiency, high selectivity, and tunable electronic structure ^[2-3]. However, there is limited understanding of how they might be optimized using activity descriptors. Here we conduct the first study on the structure-activity relationship of Fe-N-C catalysts for the catalytic transfer hydrogenation (CTH) reaction by density functional theory (DFT) calculations. We investigate the CTH mechanism of furfural to furfuryl alcohol over a set of edge-hosted Fe-N₃ sites embedded in the edge of graphene ribbons. We reveal the origin of the CTH activity at the molecular orbital level and demonstrate that the Fe 3dz² orbital plays a vital role in the binding of the hydride transfer transition state. From the geometric perspective, we find that the elevation of the Fe atom induced by the Fe-N₃ distortion strengthens the binding of adsorbates and correlates well with the CTH activity. Finally, we establish a structure-activity relationship using a simple descriptor of the Fe-N bond length. This work provides insights into the origin of CTH activity and guidelines for designing high-performance Fe-N-C catalysts.