化学
镁
氧化铁
金属
化学吸附
无机化学
化学计量学
催化作用
氧化物
一氧化碳
氢
物理化学
有机化学
标识
DOI:10.1016/0021-9517(75)90184-0
摘要
Very small and stable metallic iron particles supported on magnesium oxide have been obtained in an average size d from 1.5 to 30 nm. The hydrogen reduced particles consist of metallic iron, magnesium oxide, and Fe2+ clusters in magnesium oxide. Values of d determined by electron microscopy, magnetic susceptibility, X-ray line-broadening and Mössbauer spectra agreed with those determined by selective chemisorption of carbon monoxide with a stoichiometry of two iron atoms per adsorbed molecule. As the iron loading was changed from 1 to 40 wt %, the fraction of the iron in the metallic state on the different reduced samples varied from 0.4 to 0.7, and the Fe2+ concentration in the Fe2+ clusters in magnesium oxide varied only little. These results, coupled with a study of the sample preparation, suggest that magnesium oxide is not merely an inert carrier for metallic iron, but instead interacts with the iron in a manner essential for the ultimate production and stabilization of small metallic particles.
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