• Tafazoli, Saeede
• Yusufoğlu, Muhammed
• Kaya, Sarp
• Balkan, Timuçin

Abstract

<jats:p>Electrocatalytic activity and C2 product selectivity of two distinguished oxide-derived Cu in electrochemical carbon dioxide reduction reaction (CO<jats:sub>2</jats:sub>RR) were investigated. Cu oxide layers electrodeposited at different deposition rates exhibited different morphologies, the electrode with a more compact structure was found selective to C2 products with two times higher faradaic efficiencies (40%). Both Cu<jats:sup>+</jats:sup> and Cu<jats:sup>2+</jats:sup> species have been identified on the surface of oxide-derived Cu electrodes by X-ray photoelectron spectroscopy (XPS). Also, oxide-derived electrodes were investigated by X-ray diffraction (XRD). Results confirmed the presence of Cu oxide phases for primary electrodes, which were then fully reduced to the metallic Cu after CO<jats:sub>2</jats:sub>RR. Moreover, SEM investigations helped us distinguish the morphology of the two electrodes and monitor morphological differences before and after CO<jats:sub>2</jats:sub>RR. To shed light on the adsorbed species, intermediate (metastable) phases, and reaction mechanisms during CO<jats:sub>2</jats:sub>RR, electrochemical surface-enhanced Raman spectroscopy (SERS) was utilized. This method helped us vividly observe the formation of a metastable phase (malachite) on the electrode surface, which showed lower FEs for C2 products. Moreover, the analysis of SERS indicated a strong tie between the presence of the malachite phase and strongly adsorbed CO on electrode surfaces, preventing dimerization and further reduction. This malachite phase terminating the surface can hinder the charge transport and interfere with further reductions in C2 products.</jats:p><jats:p><jats:inline-formula><jats:inline-graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="2687fig1.jpg" xlink:type="simple" /></jats:inline-formula></jats:p><jats:p>Figure 1</jats:p><jats:p />

Topics

• Deposition
• morphology
• surface
• Carbon
• scanning electron microscopy
• x-ray diffraction
• x-ray photoelectron spectroscopy
• copper
• forming
• Raman spectroscopy
• metastable phase