Investigating the Role of Copper Oxide in Electrochemical CO2 Reduction in Real Time

• Published in: ACS applied materials & interfaces Vol. 10; no. 10; pp. 8574 - 8584
• Main Authors: Mandal, Lily, Yang, Ke R, Motapothula, Mallikarjuna Rao, Ren, Dan, Lobaccaro, Peter, Patra, Abhijeet, Sherburne, Matthew, Batista, Victor S, Yeo, Boon Siang, Ager, Joel W, Martin, Jens, Venkatesan, T
• Format: Journal Article
• Language: English
• Published: United States American Chemical Society 14-03-2018; American Chemical Society (ACS)
• Subjects: chronopotentiometry; CO adsorption; Cu2O reduction; DFT modeling; electrochemical CO2 reduction; INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY; Raman spectroscopy; CO adsorption; Cu2O reduction; electrochemical CO2 reduction; Raman spectroscopy; chronopotentiometry; DFT modeling
• ISSN: 1944-8244; 1944-8252
• DOI: 10.1021/acsami.7b15418

Copper oxides have been of considerable interest as electrocatalysts for CO2 reduction (CO2R) in aqueous electrolytes. However, their role as an active catalyst in reducing the required overpotential and improving the selectivity of reaction compared with that of polycrystalline copper remains controversial. Here, we introduce the use of selected-ion flow tube mass spectrometry, in concert with chronopotentiometry, in situ Raman spectroscopy, and computational modeling, to investigate CO2R on Cu2O nanoneedles, Cu2O nanocrystals, and Cu2O nanoparticles. We show experimentally that the selective formation of gaseous C2 products (i.e., ethylene) in CO2R is preceded by the reduction of the copper oxide (Cu2OR) surface to metallic copper. On the basis of density functional theory modeling, CO2R products are not formed as long as Cu2O is present at the surface because Cu2OR is kinetically and energetically more favorable than CO2R.