Abstract
The dissolution of Pt in aqueous electrolytes has been studied for over forty years, most recently in the context of understanding the observed loss in electrochemically-active surface area (ECA) of cathode electrocatalysts in polymer electrolyte fuel cells. Despite extensive research, there are many unresolved issues regarding the dissolution of nano-particle Pt, such as the source of the observed potential dependence of potentiostatic and potential cycling dissolution rates. To help resolve these issues, in this paper we present results of measurements of the concentration of dissolved Pt and Pt dissolution rates for carbon-supported platinum nano-particles (Pt/C) in dilute perchloric acid, as a mimic of the PEFC cathode environment, as a function of potential and upper potential limit of potential cycling. Also presented, for comparison, are results of similar studies on polycrystalline platinum. In situ Pt LIII X-ray absorption spectroscopy was used to determine the extent of oxidation, the coordination environment, and loss of Pt from the Pt nano-particles to elucidate the mechanism of Pt dissolution. Based on the correlation of these studies with those presented in the literature, mechanisms for Pt dissolution under potentiostatic and potential cycling conditions are proposed.
| Original language | English |
|---|---|
| Pages (from-to) | F3178-F3190 |
| Journal | Journal of the Electrochemical Society |
| Volume | 165 |
| Issue number | 6 |
| DOIs | |
| State | Published - 2018 |
Funding
The authors thank James Gilbert, Rodwick Barton, Junbing Yang, Di-Jia Liu, and Mali Balasubramanian for their technical help at the Advanced Photon Source and A. Jeremy Kropf for helpful discussions and for the EXAFS fitting. The authors also thank the Analytical Chemistry Laboratory and Dr. Yifen Tsai of Argonne National Laboratory for the ICP-MS analyses. The authors also wish to give a special thanks to Rajesh Ahluwalia for helpful discussions and critical review of the manuscript. The authors thank the U. S. Department of Energy (DOE), Office of Science, Basic Energy Science, Materials Science Division, for funding the X-ray portion of this work. This research used resources of the Advanced Photon Source (APS), a DOE Office of Science User Facility operated for the DOE Office of Science by Argonne National Laboratory under Contract No. DE-AC02-06CH11357. Sector 20 operations at the APS are supported by DOE and the Canadian Light Source. Electron microscopy was conducted as part of a user project at the Center for Nanophase Materials Science (CNMS), which is a U.S. DOE Office of Science User Facility. The authors thank the U.S. DOE, Office of Energy Efficiency and Renewable Energy, Fuel Cell Technologies Office, for supporting the dissolution measurement portion of this project under the guidance of Nancy Garland, DOE-EERE-FCTO Project Manager, and for supporting the data analysis and writing efforts under the auspices of the Fuel Cell Performance and Durability consortium (FC-PAD) guided by Dimitrios Papageorgopoulos, DOE-EERE-FCTO Fuel Cells Program Manager. Argonne is a U.S. Department of Energy Office of Science Laboratory operated under Contract No. DE-AC02-06CH11357 by 1201 UChicago Argonne, LLC. The views and opinions of the authors expressed herein do not necessarily state or reflect those of the United States Government or any agency thereof. Neither the United States Government nor any agency thereof, nor any of their employees, makes any warranty, expressed or implied, or assumes any legal liability or responsibility for the accuracy, completeness, or usefulness of any information, apparatus, product, or process disclosed, or represents that its use would not infringe privately owned rights.
| Funders | Funder number |
|---|---|
| DOE Office of Science User Facility operated | |
| DOE-EERE-FCTO | |
| U.S. DOE | |
| U.S. Department of Energy Office of Science Laboratory operated | |
| U.S. Department of Energy | |
| Office of Science | |
| Office of Energy Efficiency and Renewable Energy | |
| Basic Energy Sciences | |
| Argonne National Laboratory | |
| Canadian Light Source | |
| Fuel Cell Technologies Office | |
| Division of Materials Sciences and Engineering | APS |
