Abstract
We report the characterization and applications of core-shell Cu-Ir nanocatalysts for oxygen reduction reaction and oxygen evolution reaction. Core-shell Cu-Ir particles with tunable thickness of Ir can be oxidized to remove the Cu core and obtain Ir shells. The thickness of the Ir shells determines the stability and optimization of the precious metals. We showed with in situ scanning transmission electron microscopy the remarkable stability of the Ir shells at elevated temperatures under oxidative and reductive environments. In situ scanning transmission electron microscopy and in situ X-ray absorption spectroscopy also showed that traces of remaining copper could be detected in the Ir shells. Electrochemical measurements for oxygen reduction and evolution reactions show promising activity and stability compared to a commercial catalyst. Thin Ir shells, with high surface area per gram of Ir, were more active but less stable than thicker shells. In contrast, thicker Ir shells were more stable and had excellent electrochemical properties in aqueous and alkaline environments. Hence, Ir nanoshells appear as interesting candidates for reducing the cost of catalysis while improving chemical performance in fuel cells.
| Original language | English |
|---|---|
| Pages (from-to) | 4572-4580 |
| Number of pages | 9 |
| Journal | Chemistry of Materials |
| Volume | 35 |
| Issue number | 11 |
| DOIs | |
| State | Published - Jun 13 2023 |
| Externally published | Yes |
Funding
This work was primarily supported as part of the Integrated Mesoscale Architectures for Sustainable Catalysis (IMASC), an Energy Frontier Research Center funded by the U.S. Department of Energy, Office of Science, Basic Energy Sciences under Award #DE-SC0012573. This work was carried out in part at the Singh Center for Nanotechnology, which is supported by the NSF National Nanotechnology Coordinated Infrastructure Program under grant NNCI-2025608. Additional support to the Nanoscale Characterization Facility at the Singh Center has been provided by the Laboratory for Research on the Structure of Matter (MRSEC) supported by the National Science Foundation (DMR-1720530). The Swiss Light Source at Paul Scherrer Institute, Villigen, Switzerland, is acknowledged for beamline time at the microXAS beamline (X05LA). The authors appreciate useful discussions with Drs. O. Safonova and M. Nachtegaal. They also thank Dr. Chang Liu (University of Pennsylvania) for the control experiment shown in Figure S10. This work was primarily supported as part of the Integrated Mesoscale Architectures for Sustainable Catalysis (IMASC), an Energy Frontier Research Center funded by the U.S. Department of Energy, Office of Science, Basic Energy Sciences under Award #DE-SC0012573. This work was carried out in part at the Singh Center for Nanotechnology, which is supported by the NSF National Nanotechnology Coordinated Infrastructure Program under grant NNCI-2025608. Additional support to the Nanoscale Characterization Facility at the Singh Center has been provided by the Laboratory for Research on the Structure of Matter (MRSEC) supported by the National Science Foundation (DMR-1720530). The Swiss Light Source at Paul Scherrer Institute, Villigen, Switzerland, is acknowledged for beamline time at the microXAS beamline (X05LA). The authors appreciate useful discussions with Drs. O. Safonova and M. Nachtegaal. They also thank Dr. Chang Liu (University of Pennsylvania) for the control experiment shown in Figure S10 .
