DOI: 10.1002/open.201402046
Synthesis and Characterization of CeO2 Nanoparticles via
Solution Combustion Method for Photocatalytic and
Antibacterial Activity Studies
Thammadihalli Nanjundaiah Ravishankar,[a] Thippeswamy Ramakrishnappa,*[a]
Ganganagappa Nagaraju,*[b] and Hanumanaika Rajanaika[c]
CeO2 nanoparticles have been proven to be competent photo-
catalysts for environmental applications because of their
strong redox ability, nontoxicity, long-term stability, and low
cost. We have synthesized CeO2 nanoparticles via solution
combustion method using ceric ammonium nitrate as an oxi-
dizer and ethylenediaminetetraacetic acid (EDTA) as fuel at
4508C. These nanoparticles exhibit good photocatalytic degra-
dation and antibacterial activity. The obtained product was
characterized by various techniques. X-ray diffraction data con-
firms a cerianite structure: a cubic phase CeO2 having crystal-
lite size of 35 nm. The infrared spectrum shows a strong band
below 700 cmꢀ1 due to the CeꢀOꢀCe stretching vibrations.
The UV/Vis spectrum shows maximum absorption at 302 nm.
The photoluminescence spectrum shows characteristic peaks
of CeO2 nanoparticles. Scanning electron microscopy (SEM)
images clearly show the presence of a porous network with
a lot of voids. From transmission electron microscopy (TEM)
images, it is clear that the particles are almost spherical, and
the average size of the nanoparticles is found to be 42 nm.
CeO2 nanoparticles exhibit photocatalytic activity against
trypan blue at pH 10 in UV light, and the reaction follows
pseudo first-order kinetics. Finally, CeO2 nanoparticles also
reduce CrVI to CrIII and show antibacterial activity against Pseu-
domonas aeruginosa.
1. Introduction
CeO2 nanoparticles are interesting due to their wide variety of
applications in polishing agents, sunscreens, solid electrolytes,
solar cells, fuel cells, phosphorescent/luminescent materials,
photocatalysis, sensors, oxygen pumps, and metallurgy.[1]
These applications take advantage of cerium’s high thermody-
namic affinity for oxygen and sulfur, its potential redox chemis-
try involving CeIII/CeIV and the unique and useful absorption/
excitation energy bands associated with its electronic struc-
ture.[2] Cerium is a lanthanide series rare earth element and
exists as a free metal or oscillates between the CeIII and CeIV ox-
idation states. Nanoceria (cerium oxide nanoparticles) also hop
between CeIII and CeIV valence states and they contain oxygen
vacancies that allow the nanoparticles to act as regenerative
catalysts.[3]
Dyes from textile, paper, and other industries are prime ex-
amples of environmental contaminants. Nowadays, the pres-
ence of pollutant organic dyes in wastewater has become a se-
rious problem.[4,5] Among these dyes, trypan blue is one of the
most widely used dye in these industries. Trypan blue, an azo
dye reported as a carcinogen,[6] creates several environmental
problems by releasing highly toxic molecules into bodies of
water. It has a highly stable complex structure. Thus, there is
a need for an efficient and economical method for the degra-
dation of such highly photostable compounds.[7,8,9] Various
techniques available for the complete removal of toxic dyes
present in wastewater can be subdivided into four main
groups: 1) physical techniques, 2) chemical/photocatalytic deg-
radation of dyes, 3) electrochemical techniques, and 4) biologi-
cal processes.[10] Among these methods, photocatalytic degra-
dation of dyes using UV light is one of the most prominent
techniques because the reactions are carried out under ambi-
ent conditions that are cost-effective and simple.[11,12] Various
photocatalysts like TiO2, ZnO, WO3, CeO2, and ZrO2 nanoparti-
cles are used for degradation of organic dyes.[13,14] Out of these
catalysts, CeO2 nanoparticles have been proven to be compe-
tent photocatalysts for environmental applications because of
their strong redox ability, nontoxicity, long-term stability, and
low cost.[15] Various methods available to prepare CeO2 nano-
particles include hydrothermal, solvothermal, coprecipitation,
sol-gel, solution combustion, and sonochemical methods.[16,17]
Solution combustion synthesis has an edge over other meth-
ods as it is considered simple, instantaneous, single-step, and
energy saving.[18] Here we report the synthesis of CeO2 nano-
[a] T. N. Ravishankar, T. Ramakrishnappa
Centre for Nano and Material Sciences, Jain University
Jakkasandra, Kanakapura (India)
[b] G. Nagaraju
Department of Chemistry, Siddaganga Institute of Technology
Tumkur, Karnataka (India)
[c] H. Rajanaika
Department of Studies and Research in Environmental Science
Tumkur University, Tumkur, Karnataka (India)
ꢀ 2014 The Authors. Published by Wiley-VCH Verlag GmbH & Co. KGaA.
reproduction in any medium, provided the original work is properly
cited and is not used for commercial purposes.
ꢀ 2014 The Authors. Published by Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
ChemistryOpen 2014, 00, 1 – 10
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