Abstract
Catalyst size, morphology, and crystal structure play crucial roles in determining the activity and selectivity of electrochemical CO2reduction reactions, which are known to change during the reaction process. A comprehensive understanding of how, when, and why these parameters evolve under operational conditions is essential for developing stable, efficient, and selective catalysts. In this study, we reveal that formate, one of the reaction products, contributes to the degradation of copper catalysts through a ligand-assisted dissolution mechanism. Utilizing in situ electrochemical atomic force microscopy and ex-situ scanning and transmission electron microscopies, we observed a significant reduction in the size of copper nanoparticles, which decreased from over 30 nm to less than 10 nm in diameter within 60 min of CO2RR. The temporal production of formate correlated with the particle size changes. Furthermore, analysis of the electrolyte using inductively coupled plasma optical emission spectroscopy confirmed the dissolution of copper nanoparticles. Control experiments involving various reaction products (H2, CO, and HCOO–) demonstrated that formate significantly promotes copper dissolution, thereby highlighting its role in the ligand-assisted dissolution mechanism of copper electrocatalysts. Our findings provide critical insights into copper catalyst behavior during electrochemical CO2reduction, facilitating the design of more resilient and effective electrocatalysts.
| Original language | English |
|---|---|
| Pages (from-to) | 18011-18024 |
| Number of pages | 14 |
| Journal | Journal of Physical Chemistry C |
| Volume | 129 |
| Issue number | 40 |
| DOIs | |
| State | Published - Oct 9 2025 |
Funding
This work was primarily supported as part of the Center for Understanding & Controlling Accelerated and Gradual Evolution of Materials for Energy (UNCAGE-ME), an Energy Frontier Research Center funded by the U.S. Department of Energy, Office of Science, Basic Energy Sciences under award no. DE-SC0012577. A.G.S.’ contribution on ligand-promoted dissolution was supported by the U.S. Department of Energy, Office of Science, Office of Basic Energy Sciences, Chemical Sciences, Geosciences, and Biosciences Division. The characterization (SEM, TEM, and near-identical location TEM) was conducted as part of a user project at the Center for Nanophase Materials Sciences (CNMS), which is a U.S. Department of Energy, Office of Science User Facility at Oak Ridge National Laboratory. This research used resources of the National Synchrotron Light Source II, a U.S. Department of Energy (DOE) Office of Science User Facility operated for the DOE Office of Science by Brookhaven National Laboratory under Contract No. DE-SC0012704. Beamline operations were supported in part by the Synchrotron Catalysis Consortium (U.S. DOE, Office of Basic Energy Sciences, Grant No. DE-SC0012335). Harry Meier is acknowledged for XPS measurements.