Enhanced CO Oxidation Rates at the Interface of Mesoporous Oxides and Pt Nanoparticles,Journal of the American Chemical Society

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Enhanced CO Oxidation Rates at the Interface of Mesoporous Oxides and Pt Nanoparticles
Journal of the American Chemical Society ( IF 14.4 ) Pub Date : 2013-10-24 , DOI: 10.1021/ja4088743
Kwangjin An _{1,

2} , Selim Alayoglu _{1,

2} , Nathan Musselwhite _{1,

2} , Sheba Plamthottam _{1,

2} , Gérôme Melaet _{1,

2} , Avery E. Lindeman _{1,

2} , Gabor A. Somorjai _{1,

2}

Affiliation

The interaction of the metal and support in oxide-supported transition-metal catalysts has been proven to have extremely favorable effects on catalytic performance. Herein, mesoporous Co3O4, NiO, MnO2, Fe2O3, and CeO2 were synthesized and utilized in CO oxidation reactions to compare the catalytic activities before and after loading of 2.5 nm Pt nanoparticles. Turnover frequencies (TOFs) of pure mesoporous oxides were 0.0002–0.015 s(–1), while mesoporous silica was catalytically inactive in CO oxidation. When Pt nanoparticles were loaded onto the oxides, the TOFs of the Pt/metal oxide systems (0.1–500 s(–1)) were orders of magnitude greater than those of the pure oxides or the silica-supported Pt nanoparticles. The catalytic activities of various Pt/oxide systems were further influenced by varying the ratio of CO and O2 in the reactant gas feed, which provided insight into the mechanism of the observed support effect. In situ characterization using near-edge X-ray absorption fine structure (NEXAFS) and ambient-pressure X-ray photoelectron spectroscopy (APXPS) under catalytically relevant reaction conditions demonstrated a strong correlation between the oxidation state of the oxide support and the catalytic activity at the oxide–metal interface. Through catalytic activity measurements and in situ X-ray spectroscopic probes, CoO, Mn3O4, and CeO2 have been identified as the active surface phases of the oxide at the interface with Pt nanoparticles.

中文翻译：

在介孔氧化物和 Pt 纳米颗粒界面处提高 CO 氧化速率

已证明氧化物负载的过渡金属催化剂中金属和载体的相互作用对催化性能具有极其有利的影响。在此，合成了介孔 Co3O4、NiO、MnO2、Fe2O3 和 CeO2，并将其用于 CO 氧化反应，以比较负载 2.5 nm Pt 纳米粒子前后的催化活性。纯介孔氧化物的转换频率 (TOF) 为 0.0002–0.015 s(–1)，而介孔二氧化硅在 CO 氧化中无催化活性。当 Pt 纳米颗粒负载到氧化物上时，Pt/金属氧化物系统的 TOF（0.1-500 s（-1））比纯氧化物或二氧化硅负载的 Pt 纳米颗粒的 TOF 大几个数量级。各种 Pt/氧化物体系的催化活性进一步受到反应气体进料中 CO 和 O2 比例变化的影响，这提供了对观察到的支持效应机制的深入了解。在催化相关反应条件下使用近边 X 射线吸收精细结构 (NEXAFS) 和常压 X 射线光电子能谱 (APXPS) 进行的原位表征表明，氧化物载体的氧化态与催化活性之间存在很强的相关性。氧化物-金属界面。通过催化活性测量和原位 X 射线光谱探针，CoO、Mn3O4 和 CeO2 已被确定为氧化物与 Pt 纳米粒子界面处的活性表面相。在催化相关反应条件下使用近边 X 射线吸收精细结构 (NEXAFS) 和常压 X 射线光电子能谱 (APXPS) 进行的原位表征表明，氧化物载体的氧化态与催化活性之间存在很强的相关性。氧化物-金属界面。通过催化活性测量和原位 X 射线光谱探针，CoO、Mn3O4 和 CeO2 已被确定为氧化物与 Pt 纳米粒子界面处的活性表面相。在催化相关反应条件下使用近边 X 射线吸收精细结构 (NEXAFS) 和常压 X 射线光电子能谱 (APXPS) 进行的原位表征表明，氧化物载体的氧化态与催化活性之间存在很强的相关性。氧化物-金属界面。通过催化活性测量和原位 X 射线光谱探针，CoO、Mn3O4 和 CeO2 已被确定为氧化物与 Pt 纳米粒子界面处的活性表面相。

更新日期：2013-10-24

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