Improved Thermal Stability and Methane-Oxidation Activity of Pd/Al2O3 Catalysts by Atomic Layer Deposition of ZrO2

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• 作者：Tzia Ming Onn ; Shuyi Zhang ; Lisandra Arroyo-Ramirez ; Yu-Chieh Chung ; George W. Graham ; Xiaoqing Pan ; Raymond J. Gorte
• 刊名：ACS Catalysis
• 出版年：2015
• 出版时间：October 2, 2015
• 年：2015
• 卷：5
• 期：10
• 页码：5696-5701
• 全文大小：310K
• ISSN：2155-5435

文摘

The effect of modifying Pd/Al₂O₃ catalysts by atomic layer deposition of 1 nm ZrO₂ films was studied. For deposition on oxidized, PdO/Al₂O₃ catalysts, TEM imaging, EDS mapping, and metal-dispersion measurements confirmed the presence of the thin ZrO₂ over both the Al₂O₃ support and the metal particles. The ZrO₂ films were surprisingly stable, forming a well-crystallized phase only above 1173 K. The ZrO₂ coating over the PdO particles created a semicore鈥搒hell-like structure that stabilized the metal against sintering in air at 1073 K. Steady-state, methane oxidation rates on unmodified PdO/Al₂O₃ decreased with increasing catalyst calcination temperature, but rates on the ZrO₂-covered surfaces increased with increasing calcination temperature.