How do Cu nanocatalysts degrade in the presence of CO₂?

Rui Serra-Maia, Eric Stach, and their colleagues at the University of Pennsylvania and Lawrence Livermore National Laboratory used their Hummingbird Scientific in-situ liquid electrochemical TEM sample holder combined with density functional theory to investigate mechanisms of Cu nanocatalyst corrosion exposed to CO₂. The team used in-situ liquid cell transmission electron microscopy to apply various conditions to Cu catalyst nanoparticles, including CO₂ evolution reaction (CO₂ER) conditions, sub-onset for CO₂ER (E_WE = 0 V vs. SHE’), and electroless conditions with CO₂ exposure.

a) TEM images of copper corrosion in various solutions in electro-less conditions (i = 0 nA) for 15 min. b) TEM of copper corrosion in various solutions below the onset for CO₂ER (E_WE = 0 V vs. SHE’) for 15 min. c) TEM images of Cu corrosion in various solutions at E_WE = −0.8 V vs. SHE’ for 15 min. d) Cyclic voltammetry (first scan) of electroplated copper obtained for −0.8 V < E_WE vs. SHE’ < 0.2 V after introducing different CO₂ ER electrolytes into the cell. Copyright © 2025 The Authors. Published by Elsevier Inc.

Copper degradation was observed in the presence of CO₂ below the threshold conditions required for CO₂ER and without applied bias. However, no Cu degradation occurred without CO₂ even at E_WE capable of driving CO₂ER. These effects are determined from pH changes due to dissolved CO₂. Oxidized surfaces are observed in particles corroded in CO₂, but not in those exposed to CO₂-free electrolytes. DFT calculations indicate that CO₂ can behave as a dissolution agent for copper and copper-oxide surfaces, suggesting that formate-intermediate molecules are a key driver of corrosion. The study highlights the utility of the liquid-electrochemical cell in the study of nanocatalyst degradation and microenvironmental factors.

Reference: Rui Serra-Maia, Joel B. Varley, Stephen E. Weitzner, Henry Yu, Rongpei Shi, Jurgen Biener, Sneha A. Akhade, Eric A. Stach, iScience (2025) DOI: 10.1016/j.isci.2025.111851

Full paper Copyright © 2025 The Authors. Published by Elsevier Inc.

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