Electronic Tuning of CO<sub>2</sub> Interaction by Oriented Coordination of N‐Rich Auxiliary in Porphyrin Metal–Organic Frameworks for Light‐Assisted CO<sub>2</sub> Electroreduction
Zhifeng Xin, Xue Dong, Yi‐Rong Wang, Qian Wang, Kejing Shen, Jingwen Shi, Yifa Chen, Ya‐Qian Lan
Abstract
Abstract The efficient CO 2 electroreduction into high‐value products largely relies on the CO 2 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 CO 2 electroreduction. Noteworthy, thus‐obtained HMTA@MOF‐545‐Co presents approximately two times enhanced CO 2 adsorption‐enthalpy and electrochemical active surface‐area with largely decreased impedance‐value after modification, resulting in almost twice higher CO 2 electroreduction performance than its unmodified counterpart. Besides, its CO 2 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 CO 2 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 CO 2 electroreduction.