1. Preparation and characterization of Pd/C catalyst obtained in NH3-mediated polyol process
- Author
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Li, Huanqiao, Sun, Gongquan, Jiang, Qian, Zhu, Mingyuan, Sun, Shiguo, and Xin, Qin
- Subjects
- *
NANOPARTICLES , *ELECTRON microscopes , *TRANSMISSION electron microscopes , *CARBON - Abstract
Abstract: Vulcan XC-72R carbon supported Pd nanoparticles was obtained in a NH3-mediated polyol process without any protective agent and characterized by X-ray diffraction (XRD) and transmission electron microscope (TEM) techniques. The added NH3 species is found to have a strong complex ability to Pd, which not only avoids the formation of Pd hydroxide precipitate resulted from Pd hydrolysis, but also restrains the further complete reduction of Pd. Temperature-programmed reduction equipped with a mass spectrometry (TPR-MS) is employed to study the reductive behavior of unreduced Pd complex in Pd/C catalyst and the results show that the post-treatment in a reductive atmosphere at higher temperature is needed to ensure the complete reduction of Pd. XRD patterns show the heat-treated Pd/C sample in a reductive atmosphere has a face centered cubic crystal structure and TEM image indicates that the dispersion of Pd nanoparticles on the carbon support is uniform and in a narrow particle size range. Thermodynamic data analysis is carried out to elucidate the possible reaction pathway for the preparation of Pd/C catalyst in this process. The obtained Pd/C catalyst shows high activity to formic acid oxidation and high selectivity to oxygen reduction reaction (ORR) with the presence of methanol. [Copyright &y& Elsevier]
- Published
- 2007
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