Abstract
Bifunctional oxygen electrocatalysts have great potentials for energy storage and conversion applications. Here we report a facile strategy toward bifunctional electrocatalysts by supporting mixed platinum and cobalt oxide nanoparticles on carbon black. The composite electrocatalyst (denoted as Pt+CoOx/C) is found to exhibit higher oxygen evolution reaction (OER) activity than CoOx/C, but slightly lower oxygen reduction reaction (ORR) activity than Pt/C in alkaline electrolytes. The bifunctional catalytic performance is ascribed to the in situ formation of heterogenous platinum-cobalt (hydro)oxide (Pt-CoOxHy) interfaces under the electrochemical reaction conditions. Calculated electrochemical phase (Pourbaix) diagrams suggest that the migration of Co species was driven by the relative stability of Pt-CoOxHy interfaces versus bulk (hydroxy)oxides or aqueous ions of cobalt.
| Original language | English |
|---|---|
| Pages (from-to) | F3093-F3097 |
| Journal | Journal of the Electrochemical Society |
| Volume | 166 |
| Issue number | 7 |
| DOIs | |
| State | Published - 2019 |
Funding
This work was supported by the National Science Foundation (CBET-1437219) 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. Z.Z. and J.G. acknowledge the support by the U.S. Department of Energy through the Office of Science, Office of Basic Energy Sciences, Chemical, Biological, and Geosciences Division under DE-SC0010379 (J.G.) and through the Office of Energy Efficiency and Renewable Energy, under DE-EE0007270 (Z.Z.). Z.Z. and J.G. also gratefully acknowledge the computing resources provided by the Center for Nanoscale Materials, which is supported by the US Department of Energy, Office of Science, Office of Basic Energy Sciences, under E-AC02-06CH11357, as well as the computational resources through the National Energy Research Scientific Computing Center (NERSC). This work was supported by the National Science Foundation (CBET-1437219) 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. Z.Z. and J.G. acknowledge the support by the U.S. Department of Energy through the Office of Science, Office of Basic Energy Sciences, Chemical, Biological, and Geosciences Division under DESC0010379 (J.G.) and through the Office of Energy Efficiency and Renewable Energy, under DE-EE0007270 (Z.Z.). Z.Z. and J.G. also gratefully acknowledge the computing resources provided by the Center for Nanoscale Materials, which is supported by the US Department of Energy, Office of Science, Office of Basic Energy Sciences, under E-AC02-06CH11357, as well as the computational resources through the National Energy Research Scientific Computing Center (NERSC).