Enhancing CO2 Electroreduction to Methane with a Cobalt Phthalocyanine and Zinc–Nitrogen–Carbon Tandem Catalyst

Abstract

Developing copper‐free catalysts for CO 2 conversion into hydrocarbons and oxygenates is highly desirable for electrochemical CO 2 reduction reaction (CO 2 RR). Herein, we report a cobalt phthalocyanine (CoPc) and zinc–nitrogen–carbon (Zn‐N‐C) tandem catalyst for CO 2 RR to CH 4. This tandem catalyst shows a more than 100 times enhancement of the CH 4/CO production rate ratio compared with CoPc or Zn‐N‐C alone. Density functional theory (DFT) calculations and electrochemical CO reduction reaction results suggest that CO 2 is first reduced into CO over CoPc and then CO diffuses onto Zn‐N‐C for further conversion into CH 4 over Zn‐N 4 site, decoupling complicated CO 2 RR pathway on single active site into a two‐step tandem reaction. Moreover, mechanistic analysis indicates that CoPc not only generates CO but also enhances the availability of *H over adjacent N sites in Zn‐N 4, which is the key to achieve the high CH 4 production rate and understand the intriguing electrocatalytic behavior which is distinctive to copper‐based tandem catalysts.