Inexpensive and readily available copper-based catalysts are considered ideal for the electrochemical CO 2 reduction reaction (CO 2 RR) to produce multi-carbon products. The presence of copper oxides is crucial for generating high-value-added products in CO 2 RR. However, the inevitable side hydrogen evolution reaction and the easy self-reduction reaction of copper oxide under the negative potentials diminish the catalytic activity and selectivity of CO 2 RR. Currently, designing a stable phase with both resistance to electrochemical self-reduction and high CO 2 RR activity is challenging.
Recently, a research team led by Prof. Chuanxin He from Shenzhen University, China, designed to fully utilize the confinement effect and carrier effect of porous carbon nanofiber substrates on metal nanoparticles, significantly enhancing the exposure of active sites Cu/Cu x O heterojunctions at the catalytic reaction interface. The catalyst could maintain the structural stability of copper oxides under a current density of 400 mA cm ‒2 , and achieve an excellent CO 2 RR performance to ethanol with a Faradaic efficiency as high as 70.7% and a mass activity of 8.4 A mg ‒1 .
In this research, highly-dispersed copper nanoparticles within carbon nanofiber were firstly prepared via electrospinning, then the O 2 -plasma treatment was introduced to simultaneously create Cu/Cu x O heterostructure and opening mesopores throughout those carbon nanofibers. Specifically, the opening mesopores throughout carbon nanofibers can fully expose the Cu/Cu x O sites to the three-phase interface compared with untreated carbon nanofibers, leading to high and stable catalytic activity with low metal loading amount. Combined with the physical characterizations and in-situ spectral characterizations such as infrared, and Raman spectroscopy analysis, a dynamic stabilized state of Cu x O and the key signals of *CO and C–C bond are observed during the CO 2 RR process. Additionally, DFT calculations show that the presence of Cu x O promotes the spillover of *CO intermediate to the Cu/Cu x O interface, which can decrease the C–C coupling energy barrier to form C 2 H 5 OH during the CO 2 RR process. The carbon substrate can enhance electron transport and act as an electron donor to neutralize the reduction of Cu x O under a negative potential, which assists the stability of Cu/Cu x O heterostructure and maintains 213-h stability at high current densities. The results were published in Chinese Journal of Catalysis (https://doi.org/10.1016/S1872-2067(23)64604-2).
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About the Journal
Chinese Journal of Catalysis is co-sponsored by Dalian Institute of Chemical Physics, Chinese Academy of Sciences and Chinese Chemical Society, and it is currently published by Elsevier group. This monthly journal publishes in English timely contributions of original and rigorously reviewed manuscripts covering all areas of catalysis. The journal publishes Reviews, Accounts, Communications, Articles, Highlights, Perspectives, and Viewpoints of highly scientific values that help understanding and defining of new concepts in both fundamental issues and practical applications of catalysis. Chinese Journal of Catalysis ranks among the top one journals in Applied Chemistry with a current SCI impact factor of 16.5. The Editors-in-Chief are Profs. Can Li and Tao Zhang.
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Chinese Journal of Catalysis
Adequately stabilized and exposed copper heterostructure for CO2 electroreduction to ethanol with ultrahigh mass activity
21-Mar-2024