催化作用
煅烧
X射线光电子能谱
烧结
无机化学
氧化物
材料科学
降水
分解
化学工程
化学
有机化学
冶金
物理
气象学
工程类
作者
О. А. Булавченко,В. П. Коновалова,Аndrey А. Saraev,Anna M. Kremneva,Vladimir A. Rogov,E. Yu. Gerasimov,Т. Н. Афонасенко
出处
期刊:Catalysts
[MDPI AG]
日期:2022-12-27
卷期号:13 (1): 57-57
被引量:6
标识
DOI:10.3390/catal13010057
摘要
MnOx-ZrO2 catalysts prepared by co-precipitation and vacuum impregnation were calcined at 400–800 °C and characterized by powder X-ray diffraction, textural studies, high-resolution transmission electron microscopy, temperature-programmed reduction, X-ray absorption near edge structure, and X-ray photoelectron spectroscopy. The catalytic activity was tested in the CO oxidation reaction. The activity of the co-precipitated samples exceeds that of the catalysts prepared by vacuum impregnation. The characterization studies showed that the nature of the active component for the catalysts obtained by co-precipitation differs from that of the catalysts obtained by impregnation. In the impregnation series, the most active catalyst was obtained at a temperature of 400 °C; its increased activity is due to the formation of MnO2 oxide nanoparticles containing Mn4+ and low-temperature reducibility. An increase in the synthesis temperature leads to the formation of less active Mn2O3, catalyst sintering, and, accordingly, deterioration of the catalytic properties. In the case of co-precipitation, the most active CO oxidation catalysts are formed by calcination at 650–700 °C in air. In this temperature interval, on the one hand, a MnyZr1−yO2−x solid solution is formed, and on the other hand, a partial separation of mixed oxide begins with the formation of highly dispersed and active MnOx. A further increase in temperature to 800 °C leads to complete decomposition of the solid solution, the release of manganese cations into Mn3O4, and a drop in catalytic activity.
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