Screening Surface Structure-Electrochemical Activity Relationships of Copper Electrodes under CO₂ Electroreduction Conditions.

Content Provider	Europe PMC
Author	Wahab, OluwasegunJ. Kang, Minkyung Daviddi, Enrico Walker, Marc Unwin, Patrick R.
Copyright Year	2022
Abstract	Understanding howcrystallographic orientation influences the electrocatalyticperformance of metal catalysts can potentially advance the designof catalysts with improved efficiency. Although single crystal electrodesare typically used for such studies, the one-at-a-time preparationprocedure limits the range of secondary crystallographic orientationsthat can be profiled. This work employs scanning electrochemical cellmicroscopy (SECCM) together with co-located electron backscatter diffraction(EBSD) as a screening technique to investigate how surface crystallographicorientations on polycrystalline copper (Cu) correlate to activityunder CO2 electroreduction conditions. SECCM measures spatiallyresolved voltammetry on polycrystalline copper covering low overpotentialsof CO2 conversion to intermediates, thereby screening thedifferent activity from low-index facets where H2 evolutionis dominant to high-index facets where more reaction intermediatesare expected. This approach allows the acquisition of 2500 voltammogramson approximately 60 different Cu surface facets identified with EBSD.The results show that the order of activity is (111) < (100) <(110) among the Cu primary orientations. The collection of data overa wide range of secondary orientations leads to the construction ofan “electrochemical–crystallographic stereographic triangle”that provides a broad comprehension of the trends among Cu secondarysurface facets rarely studied in the literature, [particularly (941)and (741)], and clearly shows that the electroreduction activity scaleswith the step and kink density of these surfaces. This work also revealsthat the electrochemical stripping of the passive layer that is naturallyformed on Cu in air is strongly grain-dependent, and the relativeease of stripping on low-index facets follows the order of (100) >(111) > (110). This allows a procedure to be implemented, wherebythe oxide is removed (to an electrochemically undetectable level)prior to the kinetic analyses of electroreduction activity. SECCMscreening allows for the most active surfaces to be ranked and promptsin-depth follow-up studies.
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Journal	ACS Catalysis [ACS Catal]
Volume Number	12
DOI	10.1021/acscatal.2c01650
PubMed Central reference number	PMC9171721
Issue Number	11
PubMed reference number	35692254
e-ISSN	21555435
Language	English
Publisher	American Chemical Society
Publisher Date	2022-05-19
Access Restriction	Open
Rights License	Permits the broadest form of re-use including for commercial purposes, provided that author attribution and integrity are maintained (https://creativecommons.org/licenses/by/4.0/). © 2022 The Authors. Published by American Chemical Society
Subject Keyword	electrochemical reduction scanning electrochemicalcell microscopy (SECCM) copper carbon dioxide crystallographic orientation catalyst structure single entity electrochemistry
Content Type	Text
Resource Type	Article
Subject	Chemistry Catalysis