Thomas Reny Thankam, Abdul Rasheed P, Sandhyarani N
Nanoscience Research Laboratory, School of Nano Science and Technology, National Institute of Technology, Calicut, Kerala 673 601, India.
Nanoscience Research Laboratory, School of Nano Science and Technology, National Institute of Technology, Calicut, Kerala 673 601, India.
J Colloid Interface Sci. 2014 Aug 15;428:214-21. doi: 10.1016/j.jcis.2014.04.054. Epub 2014 May 2.
We report a simple method for decorating carboxyl functionalized few-layer graphene with titania (TiO2) nanoparticles by sonication and stirring under room temperature. The nanocomposites showed a remarkable improvement in visible light driven photocatalysis. From Raman and XRD analysis the number of layers of graphene was found to be 3. The TiO2 decorated few-layer graphene (FLG) sheets were characterized by electron microscopy, Raman spectroscopy, infrared spectroscopy, XRD and UV-vis spectroscopy. Titania nanoparticles were uniformly decorated on FLG matrix. The incorporation of titania on FLG enhanced the visible light photocatalytic activity of titania, lowered the electron hole recombination and improved the electron hole mobility. The enhanced life time of the charge carriers was confirmed from the photocurrent measurements. Compared to bare TiO2 nanoparticles the FLG-TiO2 nanocomposites exhibited rapid degradation of Rhodamine B (Rhd B) under solar radiation. It was found that adsorption of dye molecules and the rate of degradation have been greatly enhanced in the FLG decorated with TiO2. The rapid degradation of Rhd B using carboxyl functionalized FLG-TiO2 within 8 min under solar radiation and 20 min under 30 W UV tube with very low concentration (0.01 wt.%) of the photocatalyst is the highlight of the present report. The mechanism of degradation and charge separation ability of the nanocomposite are also explored.
我们报道了一种在室温下通过超声和搅拌用二氧化钛（TiO₂）纳米颗粒修饰羧基官能化少层石墨烯的简单方法。该纳米复合材料在可见光驱动的光催化方面表现出显著改善。通过拉曼光谱和X射线衍射分析发现石墨烯的层数为3。用电子显微镜、拉曼光谱、红外光谱、X射线衍射和紫外可见光谱对TiO₂修饰的少层石墨烯（FLG）片进行了表征。二氧化钛纳米颗粒均匀地修饰在FLG基体上。在FLG上引入二氧化钛提高了二氧化钛的可见光光催化活性，降低了电子空穴复合率并改善了电子空穴迁移率。光电流测量证实了载流子寿命的延长。与裸TiO₂纳米颗粒相比，FLG-TiO₂纳米复合材料在太阳辐射下对罗丹明B（Rhd B）表现出快速降解。发现在用TiO₂修饰的FLG中染料分子的吸附和降解速率大大提高。本报告的亮点是在太阳辐射下8分钟内以及在30 W紫外灯管下20分钟内，使用羧基官能化的FLG-TiO₂在光催化剂浓度非常低（0.01 wt.%）的情况下快速降解Rhd B。还探讨了纳米复合材料的降解机理和电荷分离能力。
