催化作用
化学
程序升温还原
电子顺磁共振
无机化学
还原(数学)
分析化学(期刊)
环境化学
有机化学
核磁共振
几何学
数学
物理
标识
DOI:10.1016/0926-860x(94)85094-1
摘要
The reduction and oxidation of Al2O3- and SiO2-supported CuCl2 has been re-investigated using TPR. The two peaks observed in the TPR profiles of dried samples are attributed to a two-step reduction of CuCL2 as opposed to previous assignments in which they were attributed to two types of immobilized cupric species with different reducibilities. EPR measurements of an Al2O3-supported sample after programmed reduction up to a point between the two TPR peaks, confirm the absence of cupric species. TPR measurements carried out after sequential treatments in C2H4, air and HCl show that the cycle CuCl2-CuCl-Cu2OCl2-CuCl2 does not occur with either support because HCl reduces the oxychloride to CuCl. It is also shown that the formation of Cu2OCl2 from CuCl requires temperatures higher than 498 K on SiO2, whereas it can be formed at room temperature on Al2O3. The addition of KC1 or LaCl3 allows the reoxidation at 498 K of the reduced species on SiO2.
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