Cu (100) grain boundaries are key to efficient CO electroreduction on commercial copper

Copper (Cu)-based catalysts are currently the most efficient for CO₍₂₎RR to produce high-value C₂₊ products. Unfortunately, despite recent advances in catalyst design for CO₍₂₎RR, a deep understanding of active sites in Cu-based catalysts remains elusive, primarily due to their poor structural stability under operating conditions, which may lead to significant reconstruction. Consequently, emerging in situ and ex situ characterizations provide ambiguousevidence regarding the true active sites of Cu-based catalysts, including morphology evolution, local pH changes, valence state shifts, crystalline surface variations, and the formation of grain boundaries. These factors likely contribute to the improved activity and selectivity for C₂₊ product evolution.

Notably, CORR can operate in highly alkaline electrolytes without forming (bi)carbonates and subsequent carbon loss. More importantly, the dynamics of C-C coupling can be enhanced in such highly basic environments to form multi-carbon (C₂₊) products. Since CO is widely recognized as a key intermediate for C-C coupling and CORR shares similar reaction pathways with CO₂RR, CORR serves as an excellent platform to deeply understand the mechanisms of CO protonation and C-C coupling, thereby facilitating the two-step pathway of CO₂ electrolysis.

Recently, a research team led by Prof. Fan Dongof University from Electronic Science and Technology of China and Prof. ShihanZhang fromZhejiang University of Technologysystematically evaluatedthe CORR performance of three typical commercial Cu-based catalysts (Cu, CuO, and Cu₂O) with different valence states in a zero-gap alkaline MEA electrolyzer. Under uniform mass transfer conditions that eliminate microenvironmental interference, they accurately identified intrinsic active sites, thereby elucidating the structure-activity relationship of CORR.The results were published in Chinese Journal of Catalysis (DOI: 10.1016/S1872-2067(25)64753-X).

Combining multidimensional characterization and theoretical calculations, this work deciphers the synergistic role of crystal planes and grain boundaries in copper-based catalysts for promoting C₂₊product formation. Initially, techniques such as XRD, XPS, in situ Raman, and CV curves systematically excluded conventional factors including Cu valence state, electrochemical active area, and local pH, narrowing the origin of activity to surface structure. Further HRTEM and OH⁻ adsorption analyses precisely identified Cu(100)-rich grain boundaries as the highly active sites. Ultimately, in situ IR and DFT simulations verified that asymmetric C–C coupling between *CHO and *CO intermediates is the preferred pathway on these sites. The outcomes offer fundamental insights into facet–boundary cooperativity and open new avenues for designing advanced Cu catalysts

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 six journals in Applied Chemistry with a current SCI impact factor of 17.7. The Editors-in-Chief are Profs. Can Li and Tao Zhang.

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