Electronic Tuning of CO₂ Interaction by Oriented Coordination of N‐Rich Auxiliary in Porphyrin Metal–Organic Frameworks for Light‐Assisted CO₂ Electroreduction

Abstract The efficient CO₂ electroreduction into high‐value products largely relies on the CO₂ adsorption/activation or electron‐transfer of electrocatalysts, thus site‐specific functionalization methods that enable boosted related interactions of electrocatalysts are much desired. Here, an oriented coordination strategy is reported to introduce N‐rich auxiliary (i.e., hexamethylenetetramine, HMTA) into metalloporphyrin metal organic frameworks (MOFs) to synthesize a series of site‐specific functionalized electrocatalysts (HMTA@MOF‐545‐M, M = Fe, Co, and Ni) and they are successfully applied in light‐assisted CO₂ electroreduction. Noteworthy, thus‐obtained HMTA@MOF‐545‐Co presents approximately two times enhanced CO₂ adsorption‐enthalpy and electrochemical active surface‐area with largely decreased impedance‐value after modification, resulting in almost twice higher CO₂ electroreduction performance than its unmodified counterpart. Besides, its CO₂ electroreduction performance can be further improved under light‐illumination and displays superior FE_CO (≈100%), high CO generation rate (≈5.11 mol m⁻² h⁻¹ at −1.1 V) and energy efficiency (≈70% at −0.7 V). Theoretical calculations verify that the oriented coordination of HMTA can increase the charge density of active sites, almost doubly enhance the CO₂ adsorption energy, and largely reduce the energy barrier of rate determining step for the boosted performance improvement. This work might promote the development of modifiable porous crystalline electrocatalysts in high‐efficiency CO₂ electroreduction.