Titanium Dioxide/Reduced Graphene Oxide Hybrid Photocatalysts for Efficient and Selective Partial Oxidation of Cyclohexane
Titanium Dioxide/Reduced Graphene Oxide Hybrid Photocatalysts for Efficient and Selective Partial Oxidation of Cyclohexane
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DOI：
10.1021/acscatal.6b02611
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发表时间：
2017-01
期刊：
影响因子：
12.9
通讯作者：
Yasuhiro Shiraishi;Shingo Shiota;H. Hirakawa;S. Tanaka;S. Ichikawa;T. Hirai
中科院分区：
文献类型：
--
作者：
Yasuhiro Shiraishi;Shingo Shiota;H. Hirakawa;S. Tanaka;S. Ichikawa;T. Hirai
分子氧部分氧化环己烷（CHA）制备环己酮（CHA-酮）是最重要的反应之一。光催化氧化已被广泛研究与二氧化钛基催化剂。然而，它们的CHA-酮选择性不足，因为所形成的CHA-酮随后通过与超氧阴离子（O2 ●-）的反应而分解，所述超氧阴离子（O2 ●-）通过O2在TiO 2上的单电子还原而产生。本文报道了TiO2与还原氧化石墨烯（rGO）杂化后，在紫外光（λ> 300 nm）下催化CHA光氧化生成CHA-酮的活性和选择性增强。TiO2/rGO杂化物产生的CHA-1的量是在裸TiO2上形成的CHA-1的两倍，具有比在裸TiO2上高得多的选择性（> 80%）（约20%）。60%）。在TiO2上光形成的导带电子被转移到rGO，促进有效的电荷分离和增强的光催化循环。在rGO上捕获的电子选择性地促进O2的双电子还原，抑制O2的双电子还原。
Partial oxidation of cyclohexane (CHA) to cyclohexanone (CHA-one) with molecular oxygen (O2) is one of the most important reactions. Photocatalytic oxidation has been studied extensively with TiO2-based catalysts. Their CHA-one selectivities are, however, insufficient because the formed CHA-one is subsequently decomposed by photocatalysis involving the reaction with superoxide anion (O2●–) produced by one-electron reduction of O2 on TiO2. Here we report that TiO2, when hybridized with reduced graphene oxide (rGO), catalyzes photooxidation of CHA to CHA-one with enhanced activity and selectivity under UV light (λ > 300 nm). The TiO2/rGO hybrids produce CHA-one with twice the amount formed on bare TiO2 with much higher selectivity (>80%) than that on bare TiO2 (ca. 60%). The conduction band electrons photoformed on TiO2 are transferred to rGO, promoting efficient charge separation and enhanced photocatalytic cycles. The trapped electrons on rGO selectively promote two-electron reduction of O2 and suppress o...