Abstract
Pt-bimetallic alloys involving 3d transition metals (Co, Ni, etc.) are promising electrocatalysts for the oxygen reduction reaction (ORR). Despite the enhanced catalytic activity versus Pt, the electrocatalytic performance of Pt-bimetallic catalysts is however limited by the lack of long-term durability, primarily due to the leaching of the non-noble element under harsh electrochemical conditions. Our study shows that the core-shell nanostructure comprising a Pt shell and a cobalt core (denoted as Co@Pt) could overcome this limitation, demonstrating ∼10 times improvement in catalytic activity versus commercial Pt catalysts and no more than 13% of loss after 30000 potential cycles. The evolutions of nanoscale and surface structures over the course of extensive potential cycling were followed by combining electron microscopic elemental mapping and electrochemical studies of CO stripping. Atomistic simulations and density functional theory calculations suggest that the core-shell nanostructure could protect the non-noble cobalt from leaching under the "electrochemical annealing" conditions while maintaining the beneficial mechanisms of bimetallic systems for catalytic activity enhancement.
| Original language | English |
|---|---|
| Pages (from-to) | 35-42 |
| Number of pages | 8 |
| Journal | ACS Catalysis |
| Volume | 8 |
| Issue number | 1 |
| DOIs | |
| State | Published - Jan 5 2018 |
Funding
This work was supported by the National Science Foundation (DMR-1410175) and the JHU Catalyst Award. The electron microscopic work was performed at the Center for Nanophase Materials Sciences (CNMS) of Oak Ridge National Laboratory, which is a user facility supported by the U.S. Department of Energy, Office of Science, and at the Irvine Materials Research Institute of the University of California, Irvine. W.G. and X.P. also acknowledge the National Science Foundation (CBET-1159240) and the School of Engineering, University of California, Irvine. Z.L. and G.W. acknowledge the support by the National Science Foundation (DMR-1410597). Z.Z. and J.G. acknowledge the Department of Energy Early Career Program through the Office of Science, Office of Basic Energy Sciences, Chemical, Biological, and Geosciences Division. Z.Z. and J.G. also gratefully acknowledge the computing resources provided by the Center for Nanoscale Materials and on Blues and Fusion, a high-performance computing cluster operated by the Laboratory Computing Resource Center, both at Argonne National Laboratory, as well as the computational resources through the National Energy Research Scientific Computing Center (NERSC). This work was supported by the National Science Foundation (DMR-1410175) and the JHU Catalyst Award. The electron microscopic work was performed at the Center for Nanophase Materials Sciences (CNMS) of Oak Ridge National Laboratory, which is a user facility supported by the U.S. Department of Energy, Office of Science, and at the Irvine Materials Research Institute of the University of California, Irvine. W.G. and X.P. also acknowledge the National Science Foundation (CBET- 1159240) and the School of Engineering, University of California, Irvine. Z.L. and G.W. acknowledge the support by the National Science Foundation (DMR-1410597). Z.Z. and J.G. acknowledge the Department of Energy Early Career Program through the Office of Science, Office of Basic Energy Sciences, Chemical, Biological, and Geosciences Division. Z.Z. and J.G. also gratefully acknowledge the computing resources provided by the Center for Nanoscale Materials and on Blues and Fusion, a high-performance computing cluster operated by the Laboratory Computing Resource Center, both at Argonne National Laboratory, as well as the computational resources through the National Energy Research Scientific Computing Center (NERSC).
Keywords
- cobalt
- core-shell nanoparticles
- electrocatalysts
- fuel cells
- oxygen reduction reaction
- platinum
