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Platinum (Pt) is an outstanding catalyst for many important industrial products. Because of its high cost and scarce reserves, it is very important to improve the performance of Pt catalysts. As the metal nanocrystals (NCs) with high-index surfaces usually show very good catalytic activity because of their high density of atomic steps and kinks, the preparation of Pt NCs with high-index facets has become a very important and hot research topic recently. In this article, we report a facile synthesis of high-yield Pt NCs with a series of {hkk} high-index facets including {211} and {411} via a solvothermal method using Pt(II) acetylacetonate as the Pt source, 1-octylamine as the solvent and capping agent, and formaldehyde as an additional surface structure regulator. Multipod Pt NCs with dominant {211} side surfaces were produced without formaldehyde, while concave Pt NCs with dominant {411} surfaces formed under the influence of formaldehyde. By analyzing the products by IR spectroscopy, we found the presence of CO on the surface of concave Pt NCs with {411} surfaces prepared from the solution containing formaldehyde. It was concluded that amine mainly stabilized the monoatomic step edges, resulting in the {211} exposed surface; with addition of formaldehyde, it decomposed into CO, leading to the formation of {411} surfaces by the additional adsorption of the CO on the {100} terraces. In addition, it was found that the as-prepared Pt NCs with high-index {211} and {411} surfaces exhibited much better catalytic activity in the electro-oxidation of ethanol than a commercial Pt/C catalyst or Pt nanocubes with low-index {100} surfaces, and the catalytic activities of Pt crystal facets decreased in the sequence {411} > {211} > {100}.


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Facile Syntheses and Enhanced Electrocatalytic Activities of Pt Nanocrystals with {hkk} High-Index Surfaces

Show Author's information Lei ZhangDingqiong ChenZhiyuan Jiang( )Jiawei ZhangShuifen XieQin KuangZhaoxiong Xie( )Lansun Zheng
Department of Chemistry and State Key Laboratory of Physical Chemistry of Solid SurfacesCollege of Chemistry and Chemical EngineeringXiamen UniversityXiamen361005China

Abstract

Platinum (Pt) is an outstanding catalyst for many important industrial products. Because of its high cost and scarce reserves, it is very important to improve the performance of Pt catalysts. As the metal nanocrystals (NCs) with high-index surfaces usually show very good catalytic activity because of their high density of atomic steps and kinks, the preparation of Pt NCs with high-index facets has become a very important and hot research topic recently. In this article, we report a facile synthesis of high-yield Pt NCs with a series of {hkk} high-index facets including {211} and {411} via a solvothermal method using Pt(II) acetylacetonate as the Pt source, 1-octylamine as the solvent and capping agent, and formaldehyde as an additional surface structure regulator. Multipod Pt NCs with dominant {211} side surfaces were produced without formaldehyde, while concave Pt NCs with dominant {411} surfaces formed under the influence of formaldehyde. By analyzing the products by IR spectroscopy, we found the presence of CO on the surface of concave Pt NCs with {411} surfaces prepared from the solution containing formaldehyde. It was concluded that amine mainly stabilized the monoatomic step edges, resulting in the {211} exposed surface; with addition of formaldehyde, it decomposed into CO, leading to the formation of {411} surfaces by the additional adsorption of the CO on the {100} terraces. In addition, it was found that the as-prepared Pt NCs with high-index {211} and {411} surfaces exhibited much better catalytic activity in the electro-oxidation of ethanol than a commercial Pt/C catalyst or Pt nanocubes with low-index {100} surfaces, and the catalytic activities of Pt crystal facets decreased in the sequence {411} > {211} > {100}.

Keywords: electrocatalysis, crystal growth, surface structure, Pt nanocrystals, high-index facets, structure–property relationship

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Publication history
Copyright
Acknowledgements

Publication history

Received: 08 November 2011
Revised: 27 December 2011
Accepted: 30 December 2011
Published: 07 February 2012
Issue date: March 2012

Copyright

© Tsinghua University Press and Springer-Verlag Berlin Heidelberg 2012

Acknowledgements

Acknowledgements

This work was supported by the National Basic Research Program of China (Grant No. 2011CBA00508), the National Natural Science Foundation of China (Grant Nos. 21131005, 21021061, 21073145, and 21171141), the National Fund for Fostering Talents of Basic Science (Grant No. J1030415), and the Key Scientific Project of Fujian Province of China (Grant No. 2009HZ0002-1).

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