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Journal of Alloys and Compounds, Volume 552, 5 March 2013, Pages 329-335
Yi-Fan Hsieh, Yu-Chi Hsieh, Yuan-Chieh Tseng, Pu-Wei Wu, Cheun Guang Chao, Pang Lin, Jyh-Fu Lee.
Department of Materials Science and Engineering, National Chiao Tung University, Hsin-Chu 30010, Taiwan, ROC
National Synchrotron Radiation Research Center, Hsin-Chu 30076, Taiwan, ROC
Abstract
We demonstrate a selective electrochemical dissolution route to prepare Cu3Pt catalysts featuring Pt-rich surface layers (Cu3Pt-Pt rich surface) from mechanically alloyed Cu3Pt. These catalysts were investigated by X-ray diffraction and X-ray absorption spectroscopy, and were subjected to electrochemical analyses to evaluate their catalytic properties. With appropriate anodization, Cu3Pt entered an oxygen-evolving regime where the corrosive dissolution of Cu dominated the reaction. Selective dissolution was carried out to prepare Pt-rich layers at the surface, while Cu3Pt was left unreacted at the core. An increase in the anodization duration modified the sample morphology, with the redistribution of Pt atoms to thicken the surface layers. A charge transfer from Pt to Cu accompanied the structural transition from Cu3Pt to Cu3Pt-Pt rich surface upon selective dissolution, rendering the sample to be electronically similar to a metal Pt. However, compared to the metal Pt and conventional Pt-based catalysts, the proposed structure is a more economical catalyst for direct methanol fuel cell, with less need of Pt in raw material but increased electrochemical surface area by exposing enormous Pt at the surface with an increase in the anodization duration.
