Three-dimensionally ordered macroporous CeO2-supported Pd@Co nanoparticles: Highly active catalysts for methane oxidation

• Published in: Journal of catalysis 2016-10, Vol.342, p.17-26
• Main Authors: Xie, Shaohua, Liu, Yuxi, Deng, Jiguang, Zhao, Xingtian, Yang, Jun, Zhang, Kunfeng, Han, Zhuo, Dai, Hongxing
• Format: Article
• Language: English
• Subjects: Catalysis; Cerium oxide; Core–shell structure; Methane; Methane oxidation; Nanoparticles; Oxidation; Porous materials; Supported Pd–Co nanocatalysts; Three dimensional imaging; Three-dimensionally ordered macropores
• ISSN: 0021-9517; 1090-2694
• DOI: 10.1016/j.jcat.2016.07.003

[Display omitted] •CoxPd are prepared using the modified polyvinyl alcohol-protected reduction method.•CoxPd nanoparticles displayed core-shell (core: Pd; shell: Co) structure.•CoxPd nanoparticles with a core-shell structure exhibit super thermal stability.•CoxPd/3DOM CeO2 possess good O2 and CH4 adsorption abilities.•CoxPd/3DOM CeO2 perform well in methane oxidation. Three-dimensionally ordered macroporous CeO2 (3DOM CeO2) and its supported Pd@Co (CoxPd/3DOM CeO2, x (Co/Pd molar ratio)=2.4–13.6) nanocatalysts were prepared using the polymethyl methacrylate-templating and modified polyvinyl alcohol-protected reduction methods, respectively. The Pd@Co particles displayed a core-shell (core: Pd; shell: Co) structure with an average size of 3.5–4.5nm and were well dispersed on the surface of 3DOM CeO2. The CoxPd/3DOM CeO2 samples exhibited high catalytic performance and super stability for methane oxidation, with the Co3.5Pd/3DOM CeO2 sample showing the highest activity (T90%=480°C at space velocity of 40,000mL/(gh) and excellent stability in the temperature range 400–800°C. The apparent activation energies (58–73kJ/mol) obtained over CoxPd/3DOM CeO2 were much lower than those (104–112kJ/mol) over Co/3DOM CeO2 and 3DOM CeO2 for methane oxidation, with the Co3.5Pd/3DOM CeO2 sample possessing the lowest apparent activation energy (58kJ/mol). It is concluded that the excellent catalytic performance of Co3.5Pd/3DOM CeO2 was associated with its good abilities to adsorb oxygen and methane as well as the unique core-shell structure of CoPd nanoparticles.