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

Abstract

<jats:p>The electrochemical reduction reaction of carbon dioxide (CO<jats:sub>2</jats:sub>RR) has garnered significant attention due to its potential for the formation of carbon monoxide, which has industrial relevance. Herein, an oxide‐derived Cu–Zn electrocatalyst with an optimized Cu<jats:sub> <jats:italic>x</jats:italic> </jats:sub>O layer that shows high selectivity toward CO with a faradic efficiency of 75% at a low overpotential (−0.8 V vs reversible hydrogen electrode) is reported. Various structural characterizations and activity tests are conducted to understand the origin of this improvement depending on the Cu<jats:sub> <jats:italic>x</jats:italic> </jats:sub>O amount. Electrochemical surface area and electrochemical impedance spectroscopy measurements suggest that the addition of Cu<jats:sub> <jats:italic>x</jats:italic> </jats:sub>O increases double‐layer capacitance and decreases charge transfer resistance. Scanning electron microscopy images indicate that the electrodes undergo a severe reconstruction process, which is further confirmed by X‐ray diffraction that shows the formation of CuZn<jats:sub>4</jats:sub> alloy during the reduction reaction. Furthermore, X‐ray photoelectron spectroscopy depth profile analysis shows that after CO<jats:sub>2</jats:sub>RR at −0.8 V, the Cu/Zn ratio is higher than that after −1.2 V, which suggests that applied potential plays a significant role in the reconstruction process and hence the difference in selectivity. The presence of copper in the surface layer has a significant impact on the improvement of selectivity toward CO.</jats:p>

Topics

• impedance spectroscopy
• surface
• Carbon
• scanning electron microscopy
• Hydrogen
• copper
• photoelectron spectroscopy