Insights into the Low Overpotential Electroreduction of CO2 to CO on a Supported Gold Catalyst in an Alkaline Flow Electrolyzer

Sumit Verma, Yuki Hamasaki, Chaerin Kim, Wenxin Huang, Shawn Lu, Huei Ru Molly Jhong, Andrew A. Gewirth, Tsuyohiko Fujigaya, Naotoshi Nakashima, Paul J.A. Kenis

Research output: Contribution to journalArticlepeer-review

Abstract

Cost competitive electroreduction of CO2 to CO requires electrochemical systems that exhibit partial current density (jCO) exceeding 150 mA cm-2 at cell overpotentials (|ηcell|) less than 1 V. However, achieving such benchmarks remains difficult. Here, we report the electroreduction of CO2 on a supported gold catalyst in an alkaline flow electrolyzer with performance levels close to the economic viability criteria. Onset of CO production occurred at cell and cathode overpotentials of just -0.25 and -0.02 V, respectively. High jCO (∼99, 158 mA cm-2) was obtained at low |ηcell| (∼0.70, 0.94 V) and high CO energetic efficiency (∼63.8, 49.4%). The performance was stable for at least 8 h. Additionally, the onset cathode potentials, kinetic isotope effect, and Tafel slopes indicate the low overpotential production of CO in alkaline media to be the result of a pH-independent rate-determining step (i.e., electron transfer) in contrast to a pH-dependent overall process.

Original languageEnglish (US)
Pages (from-to)193-198
Number of pages6
JournalACS Energy Letters
Volume3
Issue number1
DOIs
StatePublished - Jan 12 2018

ASJC Scopus subject areas

  • Chemistry (miscellaneous)
  • Renewable Energy, Sustainability and the Environment
  • Fuel Technology
  • Energy Engineering and Power Technology
  • Materials Chemistry

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