Mesoporous Co3O4 with Controlled Porosity: Inverse Micelle Synthesis and High-Performance Catalytic CO Oxidation at 鈭?0 掳C

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• 作者：Wenqiao Song ; Altug S. Poyraz ; Yongtao Meng ; Zheng Ren ; Sheng-Yu Chen ; Steven L. Suib
• 刊名：Chemistry of Materials
• 出版年：2014
• 出版时间：August 12, 2014
• 年：2014
• 卷：26
• 期：15
• 页码：4629-4639
• 全文大小：577K
• ISSN：1520-5002

文摘

Crystalline mesoporous cobalt oxides with improved catalytic activity in CO oxidation were synthesized using an inverse surfactant micelle method. The prepared materials are monodispersed nanoparticle aggregates, and the mesopores are formed by connected intraparticle voids. Powder X-ray diffraction (PXRD), N₂ sorption, field emission scanning electron microscope (FE-SEM) and high-resolution transmission electron microscopy (HR-TEM) revealed that both pore and nanoparticle sizes are enlarged with increasing thermal treatment temperatures (150鈥?50 掳C). Mesoporous cobalt oxide calcined at 350 掳C exhibited the best oxidation activity and can achieve complete oxidization (100% conversion) of CO to CO₂ at 鈭?0 掳C under normal conditions (3鈥?0 ppm of H₂O) and at 80 掳C under moisture rich conditions (3% H₂O). The commercial Co₃O₄ reached 100% conversion at 220 掳C under normal conditions. X-ray photoelectron spectroscopy (XPS), O₂-temperature-programmed desorption (O₂-TPD), H₂-temperature-programmed reduction (H₂-TPR), CO-TPD, and N₂ sorption analyses indicated that the surface oxygen vacancy and large surface area promoted the lattice oxygen mobility of the catalysts and further enhanced their catalytic performance. The catalysts were deactivated by accumulation of water and formation of carbonates, but their activities can be easily restored by expelling water and carbonates at moderate temperature (200 掳C).