Enhancing CO2 Electroreduction Selectivity toward Multicarbon Products via Tuning the Local H2O/CO2 Molar Ratio

Xiangdong Kong; Cheng Wang; Zifan Xu; Yongzhi Zhong; Yan Liu; Lang Qin; Jie Zeng; Zhigang Geng

doi:10.1021/acs.nanolett.2c02668

Enhancing CO₂ Electroreduction Selectivity toward Multicarbon Products via Tuning the Local H₂O/CO₂ Molar Ratio

Nano Lett. 2022 Oct 12;22(19):8000-8007. doi: 10.1021/acs.nanolett.2c02668. Epub 2022 Sep 9.

Authors

Xiangdong Kong¹, Cheng Wang¹, Zifan Xu¹, Yongzhi Zhong¹, Yan Liu¹, Lang Qin¹, Jie Zeng¹, Zhigang Geng¹

Affiliation

¹ Hefei National Research Center for Physical Sciences at the Microscale, CAS Key Laboratory of Strongly-Coupled Quantum Matter Physics, Key Laboratory of Surface and Interface Chemistry and Energy Catalysis of Anhui Higher Education Institutes, Department of Chemical Physics, University of Science and Technology of China, Hefei, Anhui 230026, P. R. China.

PMID: 36083633
DOI: 10.1021/acs.nanolett.2c02668

Abstract

Mass transfer plays an important role in controlling the surface coverage of reactants and the kinetics of surface reactions, thus significantly adjusting the catalytic performance. Herein, we reported that H₂O diffusion was modulated by controlling the thicknesses of the carbon black (CB) layer between the gas diffusion electrode (GDE) of Cu and the electrolyte. As a consequence, the product distribution over the GDE of Cu was effectively regulated during CO₂ electroreduction. Interestingly, a volcano-type relationship between the thickness of the CB layer and the faradaic efficiency (FE) for multicarbon (C₂₊) products was observed over the GDE of Cu. Especially, when the applied total current density was set as 800 mA cm^-2, the FE for the C₂₊ products over the GDE of Cu coated by a CB layer with a thickness of 6.6 μm reached 63.2%, which was 2.8 times higher than that (16.8%) over the GDE of Cu without a CB layer.

Keywords: C2+ products; CO2 electroreduction; H2O diffusion; Mass transfer; Reaction kinetics.