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<p>CO<sub>2</sub> electrolysis offers an attractive route for the sustainable production of ethylene. However, electrolysis in membrane electrode assembly (MEA) systems using conventional copper electrocatalysts is limited by low current densities and high operating voltages. Here we report a design strategy involving cobalt-based subsurface dopants to construct and stabilize catalytically active sites. In-depth experimental and theoretical investigations revealed that the dopants induce a shift in the rate-determining step for ethylene from CO* coupling to the chemical step: OCCO* + H* → OCCHO* + *. A Tafel slope of 54 mV per decade is observed, which is considerably lower than the value of 124 mV per decade seen for a reference copper catalyst. This enables MEA operation with a low full-cell voltage of 1.89 V at 0.5 A and stable operation for 145 h at 1 A. We showcase record MEA CO<sub>2</sub>-to-ethylene conversion at a current of 4 A, with a Faradaic efficiency of 70.6% and a full-cell energy efficiency of 25.2%. Techno-economic assessment indicates potential for profitability with a production cost close to the ethylene market price under optimistic conditions.</p><p></p>

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Ethylene electrosynthesis at low voltages enabled by dopant-induced modulation of the rate-determining step

  • 期刊论文

  • 发表日期：

    2025年7月25日

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  • Qin Yang,
  • Xiu Wang,
  • Jiguang Zhang,
  • Yu Mao,
  • Shibo Xi,
  • Yu-Chun Liu,
  • Yung-Hsi Hsu,
  • Longzhou Zhang,
  • Surani Bin Dolmanan,
  • Meng Wang,
  • Bingqing Wang,
  • Yipeng Zang,
  • Mingsheng Zhang,
  • Wan Ru Leow,
  • Sung-Fu Hung,
  • Ziyun Wang,
  • Yanwei Lum

摘要

CO2 electrolysis offers an attractive route for the sustainable production of ethylene. However, electrolysis in membrane electrode assembly (MEA) systems using conventional copper electrocatalysts is limited by low current densities and high operating voltages. Here we report a design strategy involving cobalt-based subsurface dopants to construct and stabilize catalytically active sites. In-depth experimental and theoretical investigations revealed that the dopants induce a shift in the rate-determining step for ethylene from CO* coupling to the chemical step: OCCO* + H* → OCCHO* + *. A Tafel slope of 54 mV per decade is observed, which is considerably lower than the value of 124 mV per decade seen for a reference copper catalyst. This enables MEA operation with a low full-cell voltage of 1.89 V at 0.5 A and stable operation for 145 h at 1 A. We showcase record MEA CO2-to-ethylene conversion at a current of 4 A, with a Faradaic efficiency of 70.6% and a full-cell energy efficiency of 25.2%. Techno-economic assessment indicates potential for profitability with a production cost close to the ethylene market price under optimistic conditions.