Spatially Engineered Cu(II)‐Containing Polyphosphazene‐Based Catalysts Enable Electrochemical CO 2 Reduction to Ethanol

ABSTRACT Electrochemical CO 2 reduction to value‐added multi‐carbon products is attractive, whereas the low‐efficiency C─C coupling hinders the electrocatalytic selectivity and activity. Herein, we synthesize a polyphosphazene network with a precise supramolecular configuration of the neighboring dual catalytic centers by introducing dendritic molecules. The reasonable ratio of 5,10,15,20‐tetrakis‐(4‐aminophenyl)‐porphyrin‐Cu‐(II) and hexachlorocyclotriphosphazene results in an ultrathin polymer sheath around carbon nanotubes, exhibiting π–π stacking between the adjacent porphyrin molecules and the optimized spatial distance (3.8 Å) between the neighboring Cu active sites, featuring dual‐atom catalytic centers bound to carbon nanotubes. Given the controlled geometric structure, the catalysts can boost C─C coupling reactions during CO 2 electrocatalysis, thereby improving the selectivity of the multi‐carbon product (EtOH) with a high Faradic efficiency (FE max of 61.1% at −1.0 V) in broad potential windows. The strategy of achieving precise control over the spatial distance between adjacent metal catalytic centers by incorporating dendritic molecules into a polyphosphazene network provides a viable approach for designing polymer‐based single‐atom electrocatalysts.