Enhancing CO2 Electroreduction to Methane with a Cobalt Phthalocyanine and Zinc–Nitrogen–Carbon Tandem Catalyst. (7th October 2020) - Lin, Long
Abstract: Developing copper‐free catalysts for CO2 conversion into hydrocarbons and oxygenates is highly desirable for electrochemical CO2 reduction reaction (CO2 RR). Herein, we report a cobalt phthalocyanine (CoPc) and zinc–nitrogen–carbon (Zn‐N‐C) tandem catalyst for CO2 RR to CH4 . This tandem catalyst shows a more than 100 times enhancement of the CH4 /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 CO2 is first reduced into CO over CoPc and then CO diffuses onto Zn‐N‐C for further conversion into CH4 over Zn‐N4 site, decoupling complicated CO2 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‐N4, which is the key to achieve the high CH4 production rate and understand the intriguing electrocatalytic behavior which is distinctive to copper‐based tandem catalysts. Abstract : CO2 is first electrochemically reduced into CO over CoPc. The CO then diffuses onto Zn‐N‐C for further conversion into CH4 over the Zn‐N4 site, decoupling the CO2 electroreduction pathway on a single active site into a two‐step tandem reaction which shows a more than 100 times enhancement of the CH4 /CO production rate ratio compared with CoPc or Zn‐N‐C alone.