Metal Support Interaction in Pt Nanoparticles Partially Confined in the Mesopores of Microsized Mesoporous CeO2 for Highly Efficient Purification of Volatile Organic Compounds

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• 作者：Mingyang Mao ; Haiqin Lv ; Yuanzhi Li ; Yi Yang ; Min Zeng ; Neng Li ; Xiujian Zhao
• 刊名：ACS Catalysis
• 出版年：2016
• 出版时间：January 4, 2016
• 年：2016
• 卷：6
• 期：1
• 页码：418-427
• 全文大小：616K
• ISSN：2155-5435

文摘

The Pt/CeO₂ nanocomposites of Pt nanoparticles partially confined in the mesopores of microsized mesoporous CeO₂ (1.0% Pt/CeO₂-MM) or supported on the surface of CeO₂ nanocubes (1.0% Pt/CeO₂-NC) with the same Pt loading of 1.0 wt % were prepared by the impregnation of microsized mesoporous CeO₂ or CeO₂ nanocubes with Pt(NO₃)₂ aqueous solution, followed by the reduction with NaBH₄ aqueous solution. 1.0%Pt/CeO₂-MM exhibits much higher catalytic activity for benzene oxidation than 1.0%Pt/CeO₂-NC. Compared to 1.0% Pt/CeO₂-NC, the reaction temperatures of T₅₀ and T₉₀ (corresponding to a benzene conversion = 50% and 90%) for 1.0% Pt/CeO₂-MM tremendously decreases by ΔT₅₀ = 149 °C and ΔT₉₀ = 196 °C, respectively. The turnover frequency (TOF) of 1.0% Pt/CeO₂-MM at 140 °C increases by 9.0 times as compared to that of 1.0% Pt/CeO₂-NC. The tremendous enhancement in the catalytic activity is due to a novel metal support interaction in 1.0% Pt/CeO₂-MM. The novel metal support interaction is theoretically studied by density function theory (DFT) calculation and experimentally studied by CO-TPR, CO-TPD, H₂ pulse titration, and HRTEM. The theoretical and experimental evidence reveal that the partial confinement of Pt nanoparticles in the mesopores of microsized mesoporous CeO₂ leads to a significant enhancement in the activity of the surface lattice oxygen around the interface between Pt nanoparticles and CeO₂, thus tremendously increasing the catalytic activity.