Construction of Metal–N₂O₂ Sites on Poly(ionic liquid) for Highly Efficient Electrocatalytic CO₂ Reduction

In this study, atomically dispersed metal catalysts of Salen-PIL(M) (M = Zn and Cu) for electrochemical CO 2 -to-C 1 conversion were fabricated by polymerization of a vinyl-decorated ionic liquid (IL) monomer bearing a Salen-M moiety with para -diethylbenzene. The characterization results indicated that the Salen-Zn/Cu complex was atomically dispersed in the PIL skeleton. They differed significantly in the electron transfer speed to CO 2, CO affinity, and H 2 O activation, which influenced both the activity and selectivity toward CO or CH 4 . Besides, the formation of CO 2 •–* and H 2 O activation were related to the tolerance of the pH range. Meanwhile, the adjustment of the interfacial H 2 O content by introducing a hydrophobic IL benefited the competitive CO 2 RR versus HER on Salen-PIL(Zn/Cu) catalysts. As a result, Salen-PIL(Zn) provided a CO faradaic efficiency (FE CO ) of 90.1% with a partial current density ( j CO ) of 90.1 mA cm –2 at −0.85 V, while a FE CH4 of 54.5% with j CH4 of 272.5 mA cm –2 at −1.60 V was obtained on Salen-PIL(Cu).