Spatial Heterogeneity and Strong Coupling of Fe II /Fe III in an Individual Metal-Organic Framework Nanoparticle for Efficient CO 2 Photoreduction.

The synthesis and characterization of an Fe II /Fe III metal-organic framework (MOF) nanocrystal with spatial heterogeneity that arises from the non-uniform distribution of different valence states is disclosed. The Fe II /Fe III -Ni Prussian blue analog (PBA) delivers superior photocatalytic performance in the selective CO 2 reduction reaction thanks to the strong Fe II /Fe III coupling, with CO yield up to 12.27 mmol g -1 h -1 and 90.6% selectivity under visible-light irradiation. Density functional theory calculation and experimental studies prove that the spatial heterogeneity of Fe II /Fe III in the individual MOF nanocrystal not only directs and expedites the charge transfer within a catalyst particle but also creates the heterogeneity of catalytically-active Ni sites for efficient CO 2 photoreduction. The current findings add to a growing literature of materials with compositional heterogeneity and provide a reference for future research.