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Effects of the Pt Shell Thickness on the Oxygen Reduction Reaction on a Well-Defined Pd@Pt Core-Shell Model Surface |
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| Authors: | Yuta Hashiguchi Dr Isao Nakamura Dr Tetsuo Honma Toshiyuki Matsushita Prof Haruno Murayama Prof Makoto Tokunaga Dr Yoong-Kee Choe Dr Tadahiro Fujitani |
| Institution: | 1. Chiba Research Laboratory, Corporate Research & Development, UBE Corporation, 8-1 Goiminamikaigan, Ichihara, Chiba 290-0045 Japan
Department of Chemistry, Graduate School of Science, Kyushu University, 744 Motooka, Nishiku, Fukuoka 819-0395 Japan;2. Interdisciplinary Research Center for Catalytic Chemistry, National Institute of Advanced Industrial Science and Technology (AIST), 1-1-1 Higashi, Tsukuba, Ibaraki 305-8565 Japan;3. Japan Synchrotron Radiation Research Institute (JASRI), 1-1-1, Kouto, Sayo-cho, Sayo-gun, Hyogo 679-5198 Japan;4. Chiba Research Laboratory, Corporate Research & Development, UBE Corporation, 8-1 Goiminamikaigan, Ichihara, Chiba 290-0045 Japan;5. Department of Chemistry, Graduate School of Science, Kyushu University, 744 Motooka, Nishiku, Fukuoka 819-0395 Japan;6. Research Center for Computational Design of Advanced Functional Materials, National Institute of Advanced Industrial Science and Technology (AIST), 1-1-1 Umezono, Tsukuba, Ibaraki 305-8568 Japan |
| Abstract: | The effect of the Pt shell thickness on the oxygen reduction reaction (ORR) of a Pd@Pt core-shell catalyst was studied using surface science technics and computational approaches. We found Pt shells on Pd rods to be negatively charged because of charge transfer from the Pd substrate when the shell thicknesses were 0.5 or 1 monolayer (ML). The activities of the ORR of the model surface with a Pt shell of 0.5 or 1 ML were similar and more than twice the activities of a Pt/C or Pt rod. The relationship between the ORR activity and the thickness of the Pt shell was the exact opposite of the relationship between the Pt binding energy and the Pt shell thickness. The indication was that more negatively charged Pt had higher ORR activity. Density functional theory calculations confirmed that a single layer of Pt atoms located on Pd was negatively charged compared to pure Pt and resulted in a lower barrier to the rate-limiting step of the ORR. |
| Keywords: | core-shell catalyst electrochemistry oxygen reduction heterogeneous catalysis surface chemistry |