Structural, morphological, Raman, optical, magnetic, and antibacterial characteristics of CeO₂ nanostructures

Abstract

In this study, CeO₂ nanostructures were synthesized by a soft chemical method. A hydrothermal treatment was observed to lead to an interesting morphological transformation of the nanoparticles into homogeneous microspheres composed of nanosheets with an average thickness of 40 nm. Structural analysis revealed the formation of a single-phase cubic fluorite structure of CeO₂ for both samples. A Raman spectroscopic study confirmed the XRD results and furthermore indicated the presence of a large number of oxygen vacancies in the nanosheets. These oxygen vacancies led to room-temperature ferromagnetism (RTFM) of the CeO₂ nanosheets with enhanced magnetic characteristics. Amazingly, the nanosheets exhibited substantially greater antibacterial activity than the nanoparticles. This greater antibacterial activity was attributed to greater exposure of high-surface-energy polar surfaces and to the presence of oxygen vacancies.

Keywords

cecium oxide / nanosheets / chemical synthesis / ferromagnetism / oxygen vacancies / antibacterial properties

References

[1] Yu X.J., Xie P.B., Su Q.D. Size-dependent optical properties of nanocrystalline CeO2:Er obtained by combustion synthesis. Phys. Chem. Chem. Phys., 2011, 3, 5266.

[2] Hu C.H., Xia C.H., Wang F., Zhou M., Yin P.F., Han X.Y. Synthesis of Mn-doped CeO₂ nanorods and their application as humidity sensors. Bull. Mater. Sci., 2011, 34(5): 1033.

[3] Shah V., Shah S., Shah H., Rispoli F.J., McDonnell K.T., Workeneh S., Karakoti A., Kumar A., Seal S. Antibacterial activity of polymer coated cerium oxide nanoparticles. Plos One, 2012, 7(10): e47827.

[4] Tok A.I.Y., Boey F.Y.C., Dong Z., Sun X.L. Hydrothermal synthesis of CeO₂ nano-particles. J. Mater. Process. Technol., 2007, 190(1-3): 217.

[5] Celardo I., Pedersen J.Z., Traversa E., Ghibelli L. Pharmacological potential of cerium oxide nanoparticles. Nanoscale, 2011, 3, 1411.

[6] Meng F.M., Wang L.N., Cui J.B. Controllable synthesis and optical properties of nano-CeO₂ via a facile hydrothermal route. J. Alloys Compd., 2013, 556, 102.

[7] Zhang C., Meng F.M., Wang L.N., Zhang M., Ding Z.L. Morphology-selective synthesis method of gear-like CeO₂ microstructures and their optical properties. Mater. Lett., 2014, 130, 202.

[8] Arul N.S., Mangalaraj D., Chen P.C., Ponpandian N., Meena P., Masuda Y. Enhanced photocatalytic activity of cobalt-doped CeO₂ nanorods. J. Sol Gel Sci. Technol., 2012, 64(3): 515.

[9] Atiq S., Siddiqi S.A., Abbas F., Saleem M., Ramay S.M. Carriers-assisted enhanced ferromagnetism in Al-doped ZnMnO nano-crystallites. Chin. J. Chem. Phys., 2013, 26(4): 457.

[10] Iqbal J., Jan T., Yu R.H., Naqvi S.H., Ahmad I. Doping induced tailoring in the morphology, band-gap and ferromagnetic properties of biocompatible ZnO nanowires, nanorods and nanoparticles. Nano Micro Lett., 2014, 6(3): 242.

[11] Bernardi M.I.B., Mesquita A., Béron F., Pirota K.R., de Zevallos A.O., Doriguettod A.C., de Carvalho H.B. The role of oxygen vacancies and their location in the magnetic properties of Ce1–xCuxO₂–δ nanorods. Phys. Chem. Chem. Phys., 2015, 17, 3072.

[12] Ge M.Y., Wang H., Liu E.Z., Liu J.F., Jiang J.Z., Li Y.K., Xu Z.A., Li H.Y. On the origin of ferromagnetism in CeO₂ nanocubes. Appl. Phys. Lett., 2008, 93(6): 062505.

[13] Liu Y.L., Lockman Z., Aziz A., MacManus-Driscoll J. Size dependent ferromagnetism in cerium oxide (CeO₂) nanostructures independent of oxygen vacancies. J. Phys. Condens. Matter., 2008, 20(16): 165201.

[14] Ogale S.B., Choudhary R.J., Buban J.P., Lofland S.E., Shinde S.R., Kale S.N., Kulkarni V.N., Higgins J., Lanci C., Simpson J.R., Browning N.D., Sarma S.D., Drew H.D., Greene R.L., Venkatesan T. High temperature ferromagnetism with a giant magnetic moment in transparent Co-doped SnO2–δ. Phys. Rev. Lett., 2003, 91(7): 077205-1.

[15] Wang L.N., Meng F.M. Oxygen vacancy and Ce3+ ion dependent magnetism of monocrystal CeO₂ nanopoles synthesized by a facile hydrothermal method. Mater. Res. Bull., 2013, 48(9): 3492.

[16] Bo Q.H., Meng F.M., Wang L.N. Facile hydrothermal synthesis of CeO₂ nano-octahedrons and their magnetic properties. Mater. Lett., 2014, 133, 216.

[17] Jan T., Iqbal J., Ismail M., Zakaullah M., Naqvi S.H., Badshah N. Sn doping induced enhancement in the activity of ZnO nanostructures against antibiotic resistant S. aureus bacteria. Int. J. Nanomed., 2013, 8, 3679.

[18] Li M., Zhang R., Zhang H., Feng W., Liu X. Synthesis, structural and magnetic properties of CeO₂ nanoparticles. Micro Nano Lett., 2010, 5(2): 95.

[19] Thurber A., Reddy K.M., Shutthanandan V., Engelhard M.H., Wang C., Hays J., Punnoose A. Ferromagnetism in chemically synthesized CeO₂ nanoparticles by Ni doping. Phys. Rev. B., 2007, 76, 165206.

[20] Phoka S., Laokul P., Swatsitang E., Promarak V., Seraphin S., Maensiri S. Synthesis, structural and optical properties of CeO₂ nanoparticles synthesized by a simple polyvinyl pyrrolidone (PVP) solution route. Mater. Chem. Phys., 2009, 115(1): 423.

[21] Khan S.B., Faisal M., Rahman M.M., Jamal A. Exploation of CeO₂ nanoparticles as a chemi-sensor and photo-catalyst for environmental applications. Sci. Total Environ., 2011, 409(15): 2987.

[22] Imagawa H., Sun S.H. Controlled synthesis of monodisperse CeO₂ nanoplates developed from assembled nanoparticles. J. Phys. Chem. C, 2012, 116(4): 2761.

[23] Ziegler E., Heinrich A., Oppermann H., Stöver G. Electrical properties and non-stoichiometry in ZnO single crystals. J. Phys. Status Solidi A, 1981, 66(2): 635.

[24] Phokha S., Pinitsoontorn S., Maensiri S. Room-temperature ferromagnetism in Co-doped CeO₂ nanospheres prepared by the polyvinylpyrrolidone-assisted hydrothermal method. J. Appl. Phys., 2012, 112, 113904.

[25] Wu L.J., Wiesmann H.J., Moodenbaugh A.R., Klie R.F., Zhu Y.M., Welch D.O., Suenaga M. Oxidation state and lattice expansion of CeO2–x nanoparticles as a function of particle size. Phys. Rev. B., 2004, 69, 125415.

[26] Hong N.H., Sakai J., Gervais F. Magnetism due to oxygen vacancies and/or defects in undoped semiconducting and insulating oxide thin films. J. Magn. Magn. Mater., 2007, 316(2): 214.

[27] Gandhi R.R., Gowri S., Suresh J., Sundrarajan M. Ionic liquids assisted synthesis of ZnO nanostructures: controlled size, morphology and antibacterial properties. J. Mater. Sci. Technol., 2013, 29(6): 533.

[28] Jan T., Iqbal J., Ismail M., Mahmood A. Synthesis of highly efficient antibacterial agent Ag doped ZnO nanorods: structural, Raman and optical properties. J. Appl. Phys., 2014, 115, 154308.

[29] Jan T., Iqbal J., Mansoor Q., Ismail M., Naqvi M.S.H., Gul A., Naqvi S.F.H., Abbas F. Synthesis, physical properties and antibacterial activity of Ce doped CuO: a novel nanomaterial. J. Phys. D, 2014, 47(35): 355301.