Issue 11, 2020

Time-resolved observation of C–C coupling intermediates on Cu electrodes for selective electrochemical CO2 reduction

Abstract

In the electrochemical CO2 reduction reaction (CO2RR), Cu has been spotlighted as the only electro-catalyst that can produce multi-carbon molecules, but the mechanism of the selective C2+ production reaction remains elusive. Here, we directly monitored CO2RR intermediates by employing time-resolved attenuated total reflection-surface enhanced infrared absorption spectroscopy (ATR-SEIRAS), with particular attention to the C1 and C2+ pathways beyond the formation of *CO. Electrodeposited Cu and Cu(OH)2-derived Cu were synthesized, and subsequently employed as a C1 and C2+ activating catalyst and C2+ activating catalyst, respectively. For the first time, a kinetically linked dimer intermediate (*OCCO) was observed and identified as the C2+ path triggering intermediate. The ATR-SEIRAS results suggest that C–C coupling occurs exclusively by CO dimerization toward *OCCO, without the participation of *CHO, which is an intermediate for CH4 production. In the real-time measurements, CO dimerization occurred concurrently with CO adsorption (∼5 s), while proton-coupled reduction toward *CHO has slower kinetics (∼30 s). We demonstrated that the sites showing a high vibrational frequency of *CO on the fragmented Cu surface are the potential active sites for the fast dimerization of CO. This work provides mechanistic insights into the CO2RR pathways and enables the design of efficient C2+-producing catalysts.

Graphical abstract: Time-resolved observation of C–C coupling intermediates on Cu electrodes for selective electrochemical CO2 reduction

Supplementary files

Article information

Article type
Paper
Submitted
27 מאי 2020
Accepted
18 ספט 2020
First published
18 ספט 2020

Energy Environ. Sci., 2020,13, 4301-4311

Time-resolved observation of C–C coupling intermediates on Cu electrodes for selective electrochemical CO2 reduction

Y. Kim, S. Park, S. Shin, W. Choi, B. K. Min, H. Kim, W. Kim and Y. J. Hwang, Energy Environ. Sci., 2020, 13, 4301 DOI: 10.1039/D0EE01690J

To request permission to reproduce material from this article, please go to the Copyright Clearance Center request page.

If you are an author contributing to an RSC publication, you do not need to request permission provided correct acknowledgement is given.

If you are the author of this article, you do not need to request permission to reproduce figures and diagrams provided correct acknowledgement is given. If you want to reproduce the whole article in a third-party publication (excluding your thesis/dissertation for which permission is not required) please go to the Copyright Clearance Center request page.

Read more about how to correctly acknowledge RSC content.

Social activity

Spotlight

Advertisements