Oxygen activation sites in gold and iron catalysts supported on carbon nitride and activated carbon
Oxygen activation sites in gold and iron catalysts supported on carbon nitride and activated carbon
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DOI：
10.1016/j.jcat.2010.06.018
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发表时间：
2010-09
影响因子：
7.3
通讯作者：
Junjiang Zhu;S. Carabineiro;D. Shan;J. Faria;Yujun Zhu;J. Figueiredo
中科院分区：
文献类型：
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作者：
Junjiang Zhu;S. Carabineiro;D. Shan;J. Faria;Yujun Zhu;J. Figueiredo
过渡金属和金催化剂催化氧化反应中的氧活化途径已经得到了广泛的研究，但这一问题仍在讨论中，到目前为止还没有得出一致的结论。一个可能的原因可能与这样一个事实有关，即很难确定活性氧物种是来自金属还是来自氧位置。为了解决这一问题，对无氧催化剂(Fe-C3N4)和含氧量可控的催化剂(Au/AC)进行了气相一氧化碳氧化和苯甲醇液相氧化试验。结果表明，金属中心(如Fe3+、Au)本身不能活化分子氧，催化剂的活性与用于氧活化的含氧物种(如AC表面基团)的数量密切相关。在此基础上，提出了催化剂的氧化反应方案，其中金属和氧位分别代表底物和分子氧的吸附和活化。
The pathway of oxygen activation in oxidation reactions catalyzed either by transition metal or by gold catalysts has been extensively studied; however, this topic is still under discussion, and no consistent conclusion has been achieved up to date. One possible reason for this can be related to the fact that it is hard to find out whether the activated oxygen species come from the metal or the oxygen site. In an attempt to solve this problem, catalysts without oxygen (i.e. Fe–C3N4), or with controllable oxygen content (i.e. Au/AC), were tested in the oxidation of carbon monoxide in the gas phase and the oxidation of benzyl alcohol in the liquid phase. The results indicate that the metal site (i.e. Fe3+, Au) alone is not able to activate molecular oxygen and that the activity of the catalyst depends intimately on the amount of oxygen-containing species (e.g. surface groups of AC) that are used for oxygen activation. As a result, a scheme for the oxidation reaction is proposed, where the metal and oxygen sites of the catalyst are accounted for the adsorption and activation of substrate and molecular oxygen, respectively.