NanoQAM, Department of Chemistry, Quebec Center for Functional Materials , UQAM Succ Centre Ville, CP8888, Montreal, Quebec, H3C 3P8, Canada.
State Key Laboratory of Crystal Materials, Shandong University , Jinan, 250100, China.
ACS Appl Mater Interfaces. 2016 Jan 27;8(3):1903-12. doi: 10.1021/acsami.5b10025. Epub 2016 Jan 12.
Nanocomposites composed of TiO2 and carbon materials (C) are widely popular photocatalysts because they combine the advantages of TiO2 (good UV photocatalytic activity, low cost, and stability) to the enhanced charge carrier separation and lower charge transfer resistance brought by carbon. However, the presence of carbon can also be detrimental to the photocatalytic performance as it can block the passage of light and prevent the reactant from accessing the TiO2 surface. Here using a novel interfacial in situ polymer encapsulation-graphitization method, where a glucose-containing polymer was grown directly on the surface of the TiO2, we have prepared uniform TiO2@C core-shell structures. The thickness of the carbon shell can be precisely and easily tuned between 0.5 and 8 nm by simply programming the polymer growth on TiO2. The resulting core@shell TiO2@C nanostructures are not black and they possess the highest activity for the photodegradation of organic compounds when the carbon shell thickness is 1-2 nm, corresponding to ∼3-5 graphene layers. Photoluminescence and photocurrent generation tests further confirm the crucial contribution of the carbon shell on charge carrier separation and transport. This in situ polymeric encapsulation approach allows for the careful tuning of the thickness of graphite-like carbon, and it potentially constitutes a general and efficient route to prepare other oxide@C catalysts, which can therefore largely expand the applications of nanomaterials in catalysis.
由 TiO2 和碳材料（C）组成的纳米复合材料是一种广泛流行的光催化剂，因为它们结合了 TiO2 的优点（良好的紫外光光催化活性、低成本和稳定性），以及碳带来的增强载流子分离和降低电荷转移电阻的优势。然而，碳的存在也可能对光催化性能产生不利影响，因为它会阻挡光的传播，并阻止反应物到达 TiO2 表面。在这里，我们使用了一种新颖的界面原位聚合物包裹-石墨化方法，其中含有葡萄糖的聚合物直接在 TiO2 表面生长，从而制备了均匀的 TiO2@C 核壳结构。通过简单地在 TiO2 上编程聚合物的生长，可以精确且轻松地将碳壳的厚度在 0.5 至 8nm 之间进行调节。所得的核壳 TiO2@C 纳米结构不是黑色的，当碳壳厚度为 1-2nm 时，即对应于 ∼3-5 个石墨烯层时，它们对有机化合物的光降解具有最高的活性。光致发光和光电流产生测试进一步证实了碳壳对载流子分离和传输的重要贡献。这种原位聚合包裹方法可以精确调节类石墨碳的厚度，并且可能为制备其他氧化物@C 催化剂提供一种通用且高效的途径，从而可以极大地扩展纳米材料在催化中的应用。
