Issue 6, 2020

Core–shell nanoporous AuCu3@Au monolithic electrode for efficient electrochemical CO2 reduction

Abstract

Selective conversion of carbon dioxide (CO2) to a reusable form of carbon via electrochemical reduction has attracted intensive interest for the storage of renewable energy. However, the achievement of efficient bulk monolithic electrocatalysts still remains a challenge. Herein, a facile oxidative etching of the Au20Cu80 alloy was developed for the synthesis of a monolithic nanoporous core–shell structured AuCu3@Au electrode, which showed a faradaic efficiency (FE) of 97.27% with a partial current density of 5.3 mA cm−2 at −0.6 V vs. RHE for the production of CO. The FE value is about 1.45 times higher than that over the Au nanocatalyst. Unlike single nanoporous Au, AuCu3@Au maintained an excellent performance in a broad potential window. Furthermore, a 23 cm long nanoporous AuCu3@Au bulk electrode with good ductility was prepared, over which the active current reached up to 37.2 mA with a current density of 10.78 mA cm−2 at −0.7 V vs. RHE, pushing the reduction of CO2 to industrialization. The unsaturated coordination environment with a coordination number of 8.2 over the shell gold and curved interface determined this high electrocatalytic performance. Density functional theory calculations suggested that the double-dentate adsorption structure in the AuCu3@Au catalyst effectively improves the stability of the *COOH intermediate. The density of states indicates that the introduction of Cu causes the d-band-centre of AuCu3@Au to move toward the Fermi level, directly bonding with *COOH. Therefore, the adsorption of *COOH on the surface of the AuCu3@Au catalyst is strengthened, facilitating the formation of CO. This work opens an avenue to achieve self-supported porous electrodes for various useful catalytic conversions.

Graphical abstract: Core–shell nanoporous AuCu3@Au monolithic electrode for efficient electrochemical CO2 reduction

Supplementary files

Article information

Article type
Paper
Submitted
28 Aug 2019
Accepted
06 Jan 2020
First published
07 Jan 2020

J. Mater. Chem. A, 2020,8, 3344-3350

Core–shell nanoporous AuCu3@Au monolithic electrode for efficient electrochemical CO2 reduction

X. Ma, Y. Shen, S. Yao, C. An, W. Zhang, J. Zhu, R. Si, C. Guo and C. An, J. Mater. Chem. A, 2020, 8, 3344 DOI: 10.1039/C9TA09471G

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