Divide and Conquer: Desymmetrization Separates Charge and Mass Transport in Porphyrinic Covalent Organic Frameworks for Artificial Photosynthesis

Material advances over the past decades in the recapitulation of natural photosystems have given rise to a series of functional covalent organic frameworks (COFs) for accelerating charge or mass transport. However, there has been a paucity of research addressing the functional zoning and cooperation of charge and mass transport in one COF structure. Here, we demonstrate a desymmetrization strategy that separates electron transfer, proton transport, and CO₂ binding regions in one crystalline COF to collaboratively execute artificial photosynthesis. Owing to its unique functional regionalization, the target COF with symmetry-breaking porphyrin moiety (NiSN₃Por-PDAN-COF) exhibits an exceptional CO production rate of ∼22.7 mmol g⁻¹ h⁻¹, which is ca. 65 times higher than that of the symmetric counterpart (NiN₄Por-PDAN-COF). As unveiled by advanced spectroscopies and theoretical analysis, in NiSN₃Por-PDAN-COF, the thiophene component facilitates electron transport, metal site binds CO₂, and the pyrrole moiety serves as a proton hopping site, “divide and conquer”, to synergistically elevate the conversion efficiency of artificial photosynthesis.