Biomimetic Phthalocyanine‐Based Covalent Organic Frameworks with Tunable Pendant Groups for Electrocatalytic CO2 Reduction

Abstract Electrocatalytic carbon dioxide reduction reaction (CO 2 RR) is an effective way of converting CO 2 into value‐added products using renewable energy, whose activity and selectivity can be in principle maneuvered by tuning the microenvironment near catalytic sites. Here, we demonstrate a strategy for tuning the microenvironment of CO 2 RR by learning from the natural chlorophyll and heme. Specifically, the conductive covalent organic frameworks (COFs) linked by piperazine serve as versatile supports for single‐atom catalysts (SACs), and the pendant groups modified on the COFs can be readily tailored to offer different push‐pull electronic effects for tunable microenvironment. As a result, while all the COFs exhibit high chemical structure stability under harsh conditions and good conductivity, the addition of −CH 2 NH 2 can greatly enhance the activity and selectivity of CO 2 RR. As proven by experimental characterization and theoretical simulation, the electron‐donating group (−CH 2 NH 2 ) not only reduces the surface work function of COF, but also improves the adsorption energy of the key intermediate *COOH, compared with the COFs with electron‐withdrawing groups (−CN, −COOH) near the active sites. This work provides insights into the microenvironment modulation of CO 2 RR electrocatalysts at the molecular level.