Porphyrin-Based Two-Dimensional Metal-Organic framework nanosheets for efficient photocatalytic CO2 transformation

2D metal − organic framework (MOF) nanosheets have been demonstrated to exhibit excellent properties and prospects in various aspects, especially in photocatalysis. However, the design and direct preparation of 2D MOF photocatalyst is highly desirable but still challenging. Herein, a novel 2D porphyrin-based MOF Fe-DBP(Co), which is assembled by dicarboxylic porphyrin ligands and the unprecedented undecametallic ferric-oxo clusters, is designed and developed. The unique nanosheet morphology and assembled layered structure endows the photocatalyst with higher electron-hole separation efficiency and longer photogenerated carrier lifetime compared to the analogous MOFs. Consequently, Fe-DBP(Co) exhibits strikingly excellent and stable photocatalytic performance in CO2 cycloaddition, and the reaction rate of 103.2 mmol∙g−1∙h−1 is among the state-of-the-art cases for MOF-photocatalyzed CO2 cycloaddition. The underlying mechanism investigation suggested that photogenerated electrons transferred from CoDBP ligands to the Fe clusters, and the abundant electrons and holes promoted the generation of Fe(II) and Co(III) respectively, leading to excellent catalytic performance. This work proposes a new strategy to design and develop efficient MOF photocatalysts for photocatalytic transformation of CO2.