Selective Reduction of CO2 to Methane

Luca, O. R., McCrory, C. C. L., Dalleska, N. F. & Koval, C. A. The Selective Electrochemical Conversion of Preactivated CO2 to Methane. Journal of The Electrochemical Society, 162(7), H473-476, DOI: 10.1149/2.0371507jes (2015).


Scientific Achievement

Demonstration of selective electrochemical reduction of CO2 to methane with Faradaic efficiency as high as 93%.

Significance & impact

CO2 is preactivated with an N-heterocyclic carbene, and in the presence of reducing potential and a Ni(cyclam)2+ mediator yields a 8e/8H+ selective reduction reaction to methane.

 

 

 

  The images in Luca, O. R., McCrory, C. C. L., Dalleska, N. F. & Koval, C. A. The Selective Electrochemical Conversion of Preactivated CO2 to Methane. Journal of The Electrochemical Society, 162(7), H473-476, DOI: 10.1149/2.0371507jes (2015) are licensed under a Creative Commons License (http://creativecommons.org/licenses/by/4.0/).

 

The images in Luca, O. R., McCrory, C. C. L., Dalleska, N. F. & Koval, C. A. The Selective Electrochemical Conversion of Preactivated CO2 to Methane. Journal of The Electrochemical Society, 162(7), H473-476, DOI: 10.1149/2.0371507jes (2015) are licensed under a Creative Commons License (http://creativecommons.org/licenses/by/4.0/).

13C Labeling experiments for the reduction of NHC-CO2-13C.  Top:  Chemical equation for the 13C-labeling experiment in the selective electrochemical conversion of CO2 to methane.  Bottom:  Water-resolved mass spectrum of an electrolysis headspace sample for the 13C-labeling experiment.

Research Details

  • To facilitate CO2RR selectivity, the CO2 was converted into zwitterionic NHC-CO2 carboxylate, and was reduced in the presence of a Ni mediator in a protic medium.
  • Controlled potential electrolysis combined with headspace analyses by GC-TCD and GC-MS was used to confirm the identity and the source of electrolysis products.
  • The 13C labeling experiments confirm that the source of carbon in electrochemically produced methane is from NHC-13CO2.

 

Contact:  koval@colorado.edu