Quantitatively Unraveling the Redox Shuttle of Spontaneous Oxidation/Electroreduction of CuOx on Silver Nanowires Using in Situ X-ray Absorption Spectroscopy

Chia Jui Chang, Sung Fu Hung, Chia Shuo Hsu, Hsiao Chien Chen, Sheng Chih Lin, Yen Fa Liao, Hao Ming Chen*

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

37 Scopus citations

Abstract

Oxide-derived copper catalysts have been shown to enhance CO2 reduction reaction (CO2RR) activity with high selectivity toward hydrocarbon products. However, the chemical state of oxide-derived copper during the CO2RR has remained elusive and is lacking in situ observations. Herein, a two-step process was developed to synthesize Ag nanowires coated with various thicknesses of a CuOx layer for the CO2RR. By employing in situ X-ray absorption spectroscopy, a strong correlation between the chemical state under reaction conditions and the CO2RR product profile can be revealed to validate another competing reaction (i.e., the spontaneous oxidation of Cu(0) in aqueous electrolyte) that significantly governs the chemical state of active centers of Cu. In situ Raman spectroscopy reveals the existence of reoxidation behavior under cathodic potential, and the quantification analysis of reoxidized behavior is revealed to indicate that the reoxidation rate is independent of surface morphology and strongly proportional to the electrochemically surface area. The steady oxidation state of Cu in an in situ condition is the paramount key and dominates the products' profile of the CO2RR rather than other factors (e.g., crystal facets, atomic arrangements, morphology, elements) that have been investigated in numerous reports.

Original languageEnglish
Pages (from-to)1998-2009
Number of pages12
JournalACS Central Science
Volume5
Issue number12
DOIs
StatePublished - 26 Dec 2019

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