Kumar Sachin, Ojha Animesh K, Patrice Donfack, Yadav Brajesh S, Materny Arnulf
Department of Physics, Motilal Nehru National Institute of Technology, Allahabad, Allahabad 211004, India.
Department of Physics and Earth Sciences, Jacobs University Bremen, 28759 Bremen, Germany.
Phys Chem Chem Phys. 2016 Apr 28;18(16):11157-67. doi: 10.1039/c5cp04457j.
CeO2 nanoparticles (NPs) with average particle size of ∼17 nm were grown on graphene sheets by simply mixing cerium chloride as the Ce precursor with graphene oxide (GO) in distilled water and the simultaneous reduction of GO to reduced graphene oxide (rGO), followed by a one-step hydrothermal treatment at 150 °C. A unique blue to green tuneable luminescence was observed as a function of the excitation wavelength. With this method, significant applications of rGO-CeO2 nanocomposites in many optical devices could be realized. The photocatalytic activity of the as-synthesized CeO2 and rGO-CeO2 nanocomposite was investigated by monitoring the degradation of methylene blue (MB) dye under direct sunlight irradiation. The rGO-CeO2 nanocomposite exhibited excellent photocatalytic activity compared to CeO2 NPs by degrading 90% of the MB dye in 10 min irradiation under sunlight. This property of rGO-CeO2 nanocomposites was ascribed to the significant suppression of the recombination rate of photo-generated electron-hole pairs due to charge transfer between rGO sheets and CeO2 NPs and the smaller optical band-gap in the rGO-CeO2 nanocomposite.
通过将作为铈前驱体的氯化铈与氧化石墨烯（GO）在蒸馏水中简单混合，并同时将GO还原为还原氧化石墨烯（rGO），随后在150℃进行一步水热处理，在石墨烯片上生长出平均粒径约为17nm的二氧化铈纳米颗粒（NPs）。观察到一种独特的从蓝色到绿色的可调谐发光，它是激发波长的函数。通过这种方法，可以实现rGO-CeO2纳米复合材料在许多光学器件中的重要应用。通过监测亚甲基蓝（MB）染料在阳光直射下的降解情况，研究了合成的CeO2和rGO-CeO2纳米复合材料的光催化活性。与CeO2 NPs相比，rGO-CeO2纳米复合材料在阳光下照射10分钟内降解了90%的MB染料，表现出优异的光催化活性。rGO-CeO2纳米复合材料的这种性质归因于rGO片层与CeO2 NPs之间的电荷转移以及rGO-CeO2纳米复合材料中较小的光学带隙，从而显著抑制了光生电子-空穴对的复合率。
