Enhancing CO 2 Electroreduction to C2 Products on Metal-Nitrogen Sites by Regulating H 2 O Dissociation.

Water dissociation remarkably affects the CO 2 reduction to CO and HCOOH, but whether it is effective for two-carbon product formation on M-N x -containing catalysts is still ambiguous. Herein, by using a fluorinated metal phthalocyanine (MPc-F) as the M-N 4 -based model electrocatalyst, experimental and theoretical results reveal that the H 2 O-dissociation-induced active H species decrease the overpotential of the *CO hydrogenation to *CHO and facilitate the C-C coupling between *CHO and neighboring CO. Such an effect is strengthened by an increase in the *CO binding strength on the metal center. By introducing CuPc as the H 2 O dissociation catalyst into MPc-F (MPc-F/CuPc) to accurately regulate the H 2 O dissociation, the faradic efficiency of C2 products on FePc-F/CuPc and MnPc-F/CuPc increases from 0% (FePc-F and MnPc-F) to 26 and 36%, respectively. This work develops a novel strategy for enhancing the selectivity of M-N x -containing catalysts to C2 products and reveals the correlation between H 2 O dissociation and C2 product formation.