Highly Efficient and Selective Oxidation of Aromatic Alcohols Photocatalyzed by Nanoporous Hierarchical Pt/Bi2WO6 in Organic Solvent-Free Environment
Highly Efficient and Selective Oxidation of Aromatic Alcohols Photocatalyzed by Nanoporous Hierarchical Pt/Bi2WO6 in Organic Solvent-Free Environment
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DOI：
10.1021/am507428r
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发表时间：
2015-01-21
影响因子：
9.5
通讯作者：
Bahemann, Detlef W.
中科院分区：
文献类型：
--
作者：
Qamar, M.;Elsayed, Rami B.;Bahemann, Detlef W.
从能源和环境的角度来看，芳香醇选择性转化为相应的醛具有重要意义。在此，我们描述了芳族醇（例如，4-甲氧基苄醇和4-硝基苄醇）转化为它们相应的醛。在光氧化过程中形成的对茴香醛的过氧化，直到达到全面的醇氧化观察。此外，催化剂在黑暗下表现出显著的氧化，并且转化过程与在光照下不同。考察了底物浓度、光催化剂用量和Pt负载量对乙醇氧化的影响。各种自由基清除剂的影响进行了研究，并阐明了速率决定步骤。已经设想，半导体光催化剂的还原位点在确定选择性方面起更决定性的作用，因为醇优选被氧化超过水的氧化。考察了光催化剂的化学稳定性和可回收性。
Selective conversion of aromatic alcohols into corresponding aldehydes is important from energy and environmental stance. Here, we describe highly selective (>99%) and efficient conversion (>99%) of aromatic alcohols (e.g., 4-methoxybenzyl alcohol and 4-nitrobenzyl alcohol) into their corresponding aldehydes in the presence of Pt-modified nanoporous hierarchical Bi2WO6 spheres in water under simulated sunlight at ambient conditions. Overoxidation of p-anisaldehyde, formed during photooxidation process, was not observed until comprehensive alcohol oxidation was attained. Furthermore, the catalyst showed substantial oxidation under dark and course of conversion was different than that of under light. Dependency of alcohol oxidation on substrate concentration, photocatalyst amount, and Pt loading was studied. The effect of various radical scavengers was investigated, and the rate-determining step was elucidated. It has been envisaged that the reduction site of semiconductor photocatalysts plays more decisive role in determining the selectivity as alcohol preferably get oxidized over that of water. Furthermore, the chemical stability and recyclability of the photocatalyst were investigated.