Effect of phase structure of MnO2 nanorod catalyst on the activity for CO oxidation
Effect of phase structure of MnO2 nanorod catalyst on the activity for CO oxidation
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DOI：
10.1021/jp0774995
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发表时间：
2008-04-10
影响因子：
3.7
通讯作者：
Zhu, Yongfa
中科院分区：
文献类型：
--
作者：
Liang, Shuhui;Bulgan, Fei Teng G.;Zhu, Yongfa
通过水热法合成了α-、β-、γ-和δ-MnO 2纳米棒。评价了它们对CO氧化的催化性能，并考察了相结构对MnO 2纳米棒催化活性的影响。催化剂的活性按α-→ δ- > γ- > β-MnO_2的顺序降低。CO在MnO 2纳米棒上的氧化机理如下。吸附的CO被晶格氧氧化，MnO 2纳米棒被部分还原为Mn 2 O3和Mn 3 O 4。然后，Mn 2 O3和Mn 3 O 4被气态氧氧化成MnO 2。CO的化学吸附、MnO 2的Mn-O键强度以及中间氧化物Mn 2 O3和Mn 3 O 4向MnO 2的转化对MnO 2纳米棒的活性有显著影响。MnO 2纳米棒的晶相和孔道结构对CO氧化活性起主要控制作用。
The alpha-,beta-,gamma-, and delta-MnO2 nanorods were synthesized by the hydrothermal method. Their catalytic properties for CO oxidation were evaluated, and the effects of phase structures on the activities of the MnO2 nanorods were investigated. The activities of the catalysts decreased in the order of alpha- approximate to delta- > gamma- > beta-MnO2. The mechanism of CO oxidation over the MnO2 nanorods was suggested as follows. The adsorbed CO was oxidized by the lattice oxygen, and the MnO2 nanorods were partly reduced to Mn2O3 and Mn3O4. Then, Mn2O3 and Mn3O4 were oxidized to MnO2 by gaseous oxygen. CO chemisorption, the Mn-O bond strength of the MnO2, and the transformation of intermediate oxides Mn2O3 and Mn3O4 into MnO2 can significantly influence the activity of the MnO2 nanorods. The activity for CO oxidation was mainly predominated by the crystal phase and channel structure of the MnO2 nanorods.