College of Environment and Chemical Engineering, Nanchang Hangkong University, Nanchang 330063, People's Republic of China.
Nanotechnology. 2018 Sep 28;29(39):395701. doi: 10.1088/1361-6528/aacc56. Epub 2018 Jun 13.
It is challenging to design a multifunctional structure or composite for the simultaneous adsorption and photocatalytic degradation of organic pollutants in water. Towards this goal, in this work we innovatively engineered interfacial sites between TiO particles and reduced graphene oxide (RGO) sheets by employing an in situ one-pot one-step solvothermal method. The interface was associated with the content of RGO, solvothermal time and solvent ratio of n-pentanol to n-hexane. It was found that with a moderate amount of RGO (25%), TiO nanoparticles were well dispersed on the surface of the RGO or wrapped by the RGO, thus leading to full contact and strong interactions to form a Ti-O-C interfacial structure. But with low content of RGO (6%), TiO aggregates were a mixture of nanosheets, nanoparticles and nanorods. 25%RGO/TiO also had 175% higher surface area (146 m g), 95% larger volume (0.339 cm g) and smaller band gap than 6%RGO/TiO. More importantly, 25%RGO/TiO demonstrated higher adsorption efficiency (25%) and four times faster degradation rate than TiO (0%). It also exhibited good capability to eliminate multiple organics and stable long-term cycle performance (up to 93% retention after 30 cycles). Its superiority was attributed to the large surface area and unique interface between the TiO and RGO, which not only provided more active sites to capture pollutants, but enhanced charge transfer (3 μA cm, five times higher than TiO). This work offers a promising way to purify water through engineering new material structure and integrating adsorption and photodegradation technologies.
设计一种多功能结构或复合材料以同时吸附和光催化降解水中的有机污染物具有挑战性。为此，我们创新性地采用原位一锅一步溶剂热法在 TiO 颗粒和还原氧化石墨烯（RGO）片之间构建界面。该界面与 RGO 的含量、溶剂热时间和正戊醇与正己烷的溶剂比有关。研究发现，适量的 RGO（25%）时，TiO 纳米颗粒很好地分散在 RGO 表面或被 RGO 包裹，从而实现完全接触和强烈相互作用，形成 Ti-O-C 界面结构。然而，当 RGO 含量较低（6%）时，TiO 聚集物是纳米片、纳米颗粒和纳米棒的混合物。25%RGO/TiO 的比表面积（146 m² g）比 6%RGO/TiO 高 175%，体积（0.339 cm³ g）大 95%，带隙更小。更重要的是，25%RGO/TiO 的吸附效率（25%）比 TiO（0%）高 4 倍，降解速度也快 4 倍。它还表现出良好的消除多种有机物的能力和稳定的长期循环性能（30 次循环后保留率高达 93%）。其优越性归因于 TiO 和 RGO 之间的大表面积和独特界面，不仅提供了更多的活性位点来捕获污染物，而且增强了电荷转移（3 μA cm，是 TiO 的五倍）。这项工作为通过工程新材料结构和整合吸附和光降解技术来净化水提供了一种有前景的方法。
