Transforming CdS into an efficient visible light photocatalyst for selective oxidation of saturated primary C–H bonds under ambient conditions
Transforming CdS into an efficient visible light photocatalyst for selective oxidation of saturated primary C–H bonds under ambient conditions
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DOI：
10.1039/c2sc20603j
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发表时间：
2012-07
期刊：
影响因子：
8.4
通讯作者：
Yanhui Zhang;N. Zhang;Zi-Rong Tang;Yi‐Jun Xu
中科院分区：
文献类型：
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作者：
Yanhui Zhang;N. Zhang;Zi-Rong Tang;Yi‐Jun Xu
选择性地将饱和的SP3C-H键激活为高附加值化学品，对于可持续利用现有原料来说，仍然是一项重大但具有挑战性的任务。然而，C-H键与环境友好型氧的选择性氧化往往很难控制。现有的热多相催化研究工作往往涉及到过渡金属颗粒的使用，以及反应条件的苛刻，如高温和高压，这导致了选择性的难以控制。在这里，我们报告了一种非常简单的室温方法来制备立方相、片状结构的半导体硫化镉样品。在常温常压条件下，以分子氧为良性氧化剂，以三氟化苯为溶剂，制备的硫化镉可作为可见光驱动的光催化剂，高活性、高选择性地催化烷基芳烃中饱和伯基C-H键的选择氧化。其优异的光催化性能归功于其独特的具有立方相结构的片状组装、高比表面积和光生载流子的有效分离。文中还提出了这种C-H键在硫化镉半导体上光催化选择性氧化的可能反应机理。
Selective activation of saturated sp3 C–H bonds to high-value-added chemicals remains a significant but challenging task for the sustainable exploitation of available feedstocks. However, the selective oxidation of C–H bonds with environmentally benign oxygen is often very difficult to control. Research works available in thermal heterogeneous catalysis often involve the use of transition metal particles together with harsh reaction conditions, e.g., high temperature and high pressure, which results in the difficulty in controlling the selectivity. Here, we report a very simple room temperature method to prepare a cubic phase, sheet structured semiconductor CdS sample. The as-prepared CdS is able to be used as a visible-light-driven photocatalyst for the selective oxidation of saturated primary C–H bonds in alkyl aromatics with high activity and selectivity using molecular oxygen as a benign oxidant and benzotrifluoride as the solvent under ambient conditions, i.e., room temperature and atmospheric pressure. The superior photocatalytic performance of CdS can be attributed to its unique assembly of sheet structure with cubic phase, high surface area and efficient separation of photogenerated charge carriers. The possible reaction mechanism for the photocatalytic selective oxidation of such C–H bonds over the CdS semiconductor has also been proposed.