Electrodeposition of Cu with Amino Acids toward Electrocatalytic Enhancement of CO 2 Reduction Reaction

• Published in: Journal of the Electrochemical Society Vol. 171; no. 5; p. 54507
• Main Authors: Tsuda, Yuki, Yoshii, Kazuki, Gunji, Takao, Takeda, Sahori, Takeichi, Nobuhiko
• Format: Journal Article
• Language: English
• Published: 01.05.2024
• ISSN: 0013-4651; 1945-7111
• DOI: 10.1149/1945-7111/ad44de

This study investigates the effect of five amino acids on the electrodeposition of Cu to enhance its electrocatalytic performance in CO 2 reduction reactions (CO 2 RR). The amino acids significantly influenced the deposition potential, crystallite size, and surface morphology of the electrodeposited Cu. Electrodeposited Cu with amino acids exhibit significantly smaller crystallites and higher particle density on carbon paper relative to amino acid-free samples. The integration of amino acids into the electrodeposited Cu was confirmed via high-angle annular dark-field scanning transmission electron microscopy, energy dispersive X-ray spectroscopy and hard X-ray photoelectron spectroscopy. All electrodeposited Cu exhibits a higher faradaic efficiency (FE) in the electrochemical reduction of CO 2 to CH 4 relative to Cu foil (24.2%), regardless of the presence or absence (55.0%) of amino acids when the electrolysis was conducted at −1.27 V vs RHE. Electrodeposited Cu with L-histidine, containing an imidazole group, demonstrates a higher FE of CH 4 (67.6%) and effectively suppressed the hydrogen evolution reaction, highlighting the crucial role of amino acid functional groups, particularly imidazole, in augmenting the electrochemical conversion of CO 2 to CH 4 . The study demonstrates the critical influence of specific functional groups in amino acids on the catalytic efficiency of electrodeposited Cu in CO 2 RR electrocatalysis applications.