Atomic‐Scale Spacing between Copper Facets for the Electrochemical Reduction of Carbon Dioxide

Abstract

Copper (Cu) offers a means for producing value‐added fuels through the electrochemical reduction of carbon dioxide (CO2), i.e., the CO2 reduction reaction (CO2RR), but designing Cu catalysts with significant Faradaic efficiency to C2+ products remains as a great challenge. This work demonstrates that the high activity and selectivity of Cu to C2+ products can be achieved by atomic‐scale spacings between two facets of Cu particles. These spacings are created by lithiating CuOx particles, removing lithium oxides formed, and electrochemically reducing CuOx to metallic Cu. Also, the range of spacing (ds) is confirmed via the 3D tomographs using the Cs‐corrected scanning transmission electron microscopy (3D tomo‐STEM), and the operando X‐ray absorption spectra show that oxidized Cu reduces to the metallic state during the CO2RR. Moreover, control of ds to 5–6 Å allows a current density exceeding that of unmodified CuOx nanoparticles by about 12 folds and a Faradaic efficiency of ≈80% to C2+. Density functional theory calculations support that ds of 5–6 Å maximizes the binding energies of CO2 reduction intermediates and promotes C–C coupling reactions. Consequently, this study suggests that control of ds can be used to realize the high activity and C2+ product selectivity for the CO2RR.

Boosting CO2 electroreduction towards C2+ products via CO* intermediate manipulation on copper-based catalysts

“…Numerous methods have been intensively explored to achieve this goal. Exposing the CO-preferred binding sites, engineering defects, 34,[52][53][54] controlling the oxidation state, adding promotors for CO binding and regulating the CO binding strength via substrate effects 55,56 were summarized. These methods will be discussed in detail in the following sections.…”

Copper‐Based Plasmonic Catalysis: Recent Advances and Future Perspectives

“…The exposed surface sites of Cu nanomaterials are associated with the binding strength of intermediates, further affecting the catalytic selectivity toward desired products. [ 183–185 ] Sargent and coworkers synthesized Cu catalyst via in situ electrodeposition of copper under CO 2 reduction conditions, which preferentially exposed and maintained Cu(100) facets. [ 183 ] The Cu(100)‐rich catalyst favors the formation of C 2+ products, achieving a constant C 2 H 4 selectivity for 65 h. Huang et al.…”

“…explored the structure activity of (100), (110), and (111) facets of Cu NPs toward WGS, indicating that the reaction rate of Cu NCs enclosed with {100} facets is almost 5 times than that of Cu octahedra enclosed with {111} facets up to 548 K. [ 184 ] Recently, it is reported that tuning atomic‐scale spacing between two facets of Cu NPs also attains the high activity and selectivity of C 2+ products in CO 2 RR. [ 185 ] Consequently, summarizing catalytic properties of different surface sites of catalysts is beneficial to identify active centers and further develop rational design strategies for highly efficient photocatalysts.…”

Nanostructured Anodic Copper Oxides as Catalysts in Electrochemical and Photoelectrochemical Reactions

“…Oxidation of CO 2 RR intended copper electrodes yields various types of nanostructures depending on method, process conditions and oxidizing agents. As it was reported, nanowires (NW) [91,92], nanoneedles (NN) [93], nanocrystals (NC) [94,95], and nanoparticles (NP) [96,97] of copper oxides and/or hydroxides can be produced during OD-Cu catalyst preparation. Gao et al [98] reported ECSA of O 2 -plasma oxidized Cu that was 44 times larger than parent Cu flat foil after 1 h of CO 2 RR.…”