Enhanced CO2 Photoreduction through Spontaneous Charge Separation in End‐Capping Assembly of Heterostructured Covalent‐Organic Frameworks

reduction, with an efficiency of 8-fold higher than that of unmodified COF. A combination of electrochemical, steady-state, and time-resolved spectroscopic measurements indicates that such drastically enhanced performance should be attributed to photoinduced spontaneous charge separation in the heterostructure. These results illustrate the feasibility of engineering the charge-separation properties of crystalline porous frameworks at a molecular level for artificial photosynthesis.