<p>Electrochemical CO<sub>2</sub>-to-ethanol conversion is&#xa0;challenged by sluggish C-C coupling kinetics and&#xa0;wide products distribution. Although&#xa0;Cu<sup>+</sup>&#xa0;has been demonstrated to enhance multi-carbon (C<sub>2+</sub>) formation, the stabilization of&#xa0;Cu<sup>+</sup> under reduction conditions is difficult. Here, we report a hydrogen-ethanol pretreatment strategy to obtain Cu nanoparticles covered by highly dispersed and disordered ZnO<sub>1-<i>x</i></sub> clusters. Ethanol-induced ZnO<sub>1-<i>x</i></sub> redispersion gives rise to abundant Cu<sup>+</sup> on the subsurface. The optimal&#xa0;catalyst delivers a 73.0% ethanol Faradaic efficiency (FE) and 86.0% total C<sub>2+</sub> FE at −0.9 V, with a 2.3 mmol cm<sup>−2</sup> h<sup>−1</sup> ethanol formation rate and single-pass ethanol yield of 18.0%. The catalyst also&#xa0;exhibits stability beyond 500 h, attributed to the stabilization of Cu<sup>+</sup> by&#xa0;the ZnO<sub>1-<i>x</i></sub> shield that requires&#xa0;a high energy barrier for lattice oxygen removal. In situ X-ray spectroscopy and calculations reveal a volcano relationship between Cu<sup>+</sup> ratio in Cu species and ethanol FE. Optimal Cu<sup>+</sup> density not only&#xa0;facilitates *OC-COH coupling but also&#xa0;optimizes the adsorption energy of *CH<sub>2</sub>CH<sub>2</sub>O on catalyst for ethanol electrosynthesis.</p>

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In situ stabilization of Cu+ for CO2 Electroreduction via Environmental-molecules-induced ZnO1-x shield

  • Fanxing Zhang,
  • Ning Cao,
  • Chentao Wang,
  • Shengxiang Wang,
  • Yi He,
  • Yao Shi,
  • Mi Yan,
  • Ying Bao,
  • Zhenglong Li,
  • Pengfei Xie

摘要

Electrochemical CO2-to-ethanol conversion is challenged by sluggish C-C coupling kinetics and wide products distribution. Although Cu+ has been demonstrated to enhance multi-carbon (C2+) formation, the stabilization of Cu+ under reduction conditions is difficult. Here, we report a hydrogen-ethanol pretreatment strategy to obtain Cu nanoparticles covered by highly dispersed and disordered ZnO1-x clusters. Ethanol-induced ZnO1-x redispersion gives rise to abundant Cu+ on the subsurface. The optimal catalyst delivers a 73.0% ethanol Faradaic efficiency (FE) and 86.0% total C2+ FE at −0.9 V, with a 2.3 mmol cm−2 h−1 ethanol formation rate and single-pass ethanol yield of 18.0%. The catalyst also exhibits stability beyond 500 h, attributed to the stabilization of Cu+ by the ZnO1-x shield that requires a high energy barrier for lattice oxygen removal. In situ X-ray spectroscopy and calculations reveal a volcano relationship between Cu+ ratio in Cu species and ethanol FE. Optimal Cu+ density not only facilitates *OC-COH coupling but also optimizes the adsorption energy of *CH2CH2O on catalyst for ethanol electrosynthesis.