Nitrogen-rich carbon nitride inducing electron delocalization of Co-N4 site to enhance electrocatalytic carbon dioxide reduction

Cobalt phthalocyanine (CoPc) is an appealing electrocatalyst for CO2 reduction. However, its catalytic performance is limited by instability and low conductivity. Herein, theoretical calculations reveal that nitrogen-rich carbon nitride, as a promising Supporting material, can help to tune the electronic structure of CoPc and then enhance its stability and conductivity by inducing electron delocalization of Co-N4 sites for the formation of Co-N5, achieving a superior electrochemical reduction of CO2. Inspired by this prediction, we prepared nitrogen-rich carbon nitride that coordinated with Co-N4 through axial N coordination under 400 ºC, forming an atomically dispersed Co-N5 catalytic site. The synthesized catalyst demonstrates excellent performance in CO2 conversion to CO with >99 % selectivity at a current density of − 5.3 mA cm-2, which can remain for 40 h. These findings provide a strategy for regulating catalytic sites and shed light on expanding the applications of low-cost carbon nitride materials at mild heat-treatment temperatures.