SPECTROSCOPIC STUDY OF SUPEROXIDE SPECIES FORMED BY LOW-TEMPERATURE ADSORPTION OF OXYGEN ONTO COO-MGO SOLID-SOLUTIONS - AN EXAMPLE OF SYNTHETIC HETEROGENEOUS OXYGEN CARRIERS
SPECTROSCOPIC STUDY OF SUPEROXIDE SPECIES FORMED BY LOW-TEMPERATURE ADSORPTION OF OXYGEN ONTO COO-MGO SOLID-SOLUTIONS - AN EXAMPLE OF SYNTHETIC HETEROGENEOUS OXYGEN CARRIERS
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DOI：
10.1021/j100281a008
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发表时间：
1986-11-06
影响因子：
--
通讯作者：
ZECCHINA, A
中科院分区：
文献类型：
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作者：
GIAMELLO, E;SOJKA, Z;ZECCHINA, A
用IR和EPR研究了CoO-MgO稀固溶体在77 ~ 298 K之间对氧的吸附。在77 K下，稳定在钴中心上的不同超氧化物物种的特征在于1020和1220 cm-1之间的IR谱带和典型的端对吸附的EPR谱。不同物种的存在是由于表面的不均匀性和带电氧与相邻正离子的静电相互作用。在温度升高时，在77 K下形成的物种引起Oz”稳定到Mg 2+离子上，并产生新的钴超氧化物加合物。这项研究证明了两种类型的Co2+离子。当第一种在氧吸附时被不可逆地氧化为Co ~（3+）时，第二种可逆地结合分子氧，表现为非均相氧载体。
The adsorption of oxygen onto CoO-MgO dilute solid solutions has been studied between 77 and 298 K by IR and EPR. At 77 K, different superoxide species stabilized onto cobalt centers are characterized by IR bands between 1020 and 1220 cm" 1 and EPR spectra typicalof end-on adsorption. The presence of different species is due tothe heterogeneity of the surface and to electrostatic interactionsof the charged oxygen with neighboring positive ions. On increasing the temperature, the species formed at 77 K give rise to Oz" stabilized onto Mg2+ ions and to a new cobalt superoxide adduct. This study evidences two types of Co2+ ions. While the first one is irreversibly oxidizedto Co3+ on oxygen adsorption, the second which reversibly binds dioxygen behaves as a heterogeneous oxygen carrier.