Volume 10, Issue 2, 2020, 5306 - 5311 ISSN 2069-5837 Biointerface Research in Applied Chemistry www.BiointerfaceResearch.com https://doi.org/10.33263/BRIAC102.306311 Original Research Article Open Access Journal Received: 04.02.2020 / Revised: 17.02.2020 / Accepted: 18.02.2020 / Published on-line: 20.02.2020 Synthesis and characterization of pure and Cu doped CeO2 nanoparticles: photocatalytic and antibacterial activities evaluation 1 1 2 Govindarasu Killivalavan , Arthur Charles Prabakar , K. Chandra Babu Naidu , Balaraman 3, * 3 4 Sathyaseelan , Gubendiran Rameshkumar , Dhananjayan Sivakumar , Krishnamoorthy 5 6 7 8 Senthilnathan , Iruson Baskaran , Elayaperumal Manikandan , B. Ramakrishna Rao 1 Research and Development Center, Bharathiar University, Coimbatore-641046, India 2 Department of Physics, GITAM Deemed to be University, Bangalore-562163, Karnataka, India 3 Department of Physics, University College of Engineering Arni , Anna University Chennai, Arni 632326, Tamil Nadu, India. 4 Department of Physics, Sree Krishna College of Engineering,Unai,Anaicut-632101,Tamilnadu,India. 5 Photonics Division, School of Advanced Sciences, VIT University, Vellore, 632014, Tamil Nadu, India 6 Department of Physics Arignar Anna Government Arts College, Cheyyar 604407, Tamil Nadu, India 7 Department of Physics, Thiruvalluvar University College of Arts and Science, Thennangur Village, Vandavasi Taluk, Tiruvannamalai District 604408, India 8 Department of Chemistry, GITAM Deemed to be University, Bangalore-562163, Karnataka, India *corresponding author e-mail address: [email protected] | Scopus ID 35734996700 ABSTRACT This article reports the effect of pure CeO2 and Cu (1%, 3% and 5 mol %) doped CeO2 Nanoparticles (NPs) have been prepared by very simple and improved co-precipitation method. Synthesized NPs has been subjected to several analytical methods, viz. XRD, TEM and UV-Vis spectral analysis. XRD data analysis confirmed that face cubic structure and average size are found to be in the range 5-10nm. Particle size and morphological studies as observed from TEM exhibits almost identical cubical shaped particles with average size 5- 8nm. The tuning of band gap energy has been observed from UV-Visible absorption spectrum of cerium oxide NPs upon Cu (1%, 3%, and 5mol %) incorporation. Degradation of the methylene blue (MB) through photocatalysis has been observed for pure and Cu (1%, 3% and 5 mol%) CeO2 nanoparticles under solar spectrum. In addition, pure and Cu (1%, 3% and 5 mol %) cerium oxide nanoparticles has also been subjected to antibacterial response using different strains. Keywords: Nanocrystalline Materials,Structural , Co-Precipitation, XRD, SEM, HRTEM, Antibacterial Activity. 1. INTRODUCTION Most of the organic pollutants discharged from textiles the large solar absorption spectrum and electron-hole pair industry are toxic and non-biodegradable by ecological process in recombination is one of the key factors that enhance the nature and it’s greatly contaminates water and make environment photocatalytic activity process is due to rapid charge pollutions. Water is precious natural resources on the earth and it recombination contributes to low efficiency [5, 6]. has been polluted mainly by contaminated waste water without Metal ions doped cerium oxide has been considered an proper purification from the textile industry [1, 2]. effective approach to modify physical and chemical properties Oxide semiconductor based photocatalysts shown great especially copper (Cu2+) ion has an incomplete d orbit level is potential for effective degradation of organic compounds causing capable metal to produce large number of electron and having the water pollution. The photocatalytic activity of oxide ability to retard photo-generated charges. Cu2+ ionic radius is semiconductor can be tuned by controlling and reducing comparable with Ce3+ (or) Ce4+ ions, so the doping level of Cu2+ in recombination of charge carriers. Metal oxide like TiO2, ZnO2, cerium oxide can be easily controlled. Doping of copper ion into SnO2, and Fe2O3 are widely studied in the various field of waste cerium oxide induces more oxygen vacancies and it improves the water purification fields. CeO2 is capable of existing in different photocatalytic activity. Several chemical routes such as co- oxidation states consequent to its oxygen release/supply. In precipitation [7], hydrothermal technique [8], sol-gel [9], photocatalysis, CeO2 has drawn considerable attraction due to its electrodeposition [10], etc., have been used to synthesis the cerium outstanding photochemical stable, non-toxicity and economically oxide nanoparticles. low. Besides, CeO2 reveals strong optical specturm in the UV- Among those techniques we have chosen co-precipitation visible region that is comparable to TiO2 photocatalysts. Hence, technique because of low cost, easy to scale up and ecofriendly. In Cerium oxide nanoparticle is likely to be the most appropriate this work, metal ion (Cu) at various concentrations (1mol%, alternative candidate to TiO2 since energy band gap of CeO2 is 3mol% and 5mol%) doped cerium oxide NPs synthesized by co- moreover similar to TiO2 (3.2 eV) [3, 4]. Nanostrucutred CeO2 is a precipitation method and their influence on their structural, rare earth oxide that has been identified in the purification of morphology, photocatalytic activity and antimicrobial properties waste water due to the large band gap (~3.5 eV) when compared against some bacteria species were investigated. with other metal oxides. The nanosized CeO2 particles exhibit like large surface area, average particle size, microstructural and scrap Page | 5306 Synthesis and characterization of pure and Cu doped CeO2 nanoparticles: photocatalytic and antibacterial activities evaluation 2. MATERIALS AND METHODS Cerium oxide ultrafine particles were prepared through 2.1. Characterization of virgin and Cu-doped CeO2 simple precipitation method which comprises sequential steps of nanoparticles. (i) mixing, (ii) stirring and (iii) drying. An aqueous solution of Powder X-ray diffraction was recorded in the 2θ region 15- Ce(NO3)3•6H2O has been initially prepared. Then, a few drops 80° (Bruker, D8 Diffractometer) at a scan rate 2°/min with the aid solution of NaOH and polyethylene glycol (PEG) was added to the of Cu-Kα1 source. Scherrer approach was adopted to estimate the base and its pH is maintained at 11. The solution was stirred well average size of the CeO2 crystallites. Topographical images have until precipitation occurs. The precipitates were washed, dried and been recorded using SEM analysis and from EDX measurements, the resulting mixture is heated up to a temperature of 110ºCfor 24 composition of individual elemens was also assessed using Carl h. Zeiss SUPRA-555 scanning electron microscope. In order to Cu-doped CeO2 nanoparticles were prepared in three ascertain the results obtained from SEM, Transmission electron compositions via 1, 3 and 5 mol% by dissolving Cerium nitrate microscope has also been studied using PHILIPS, Model: CM200 hexahydrate and copper nitrate trihydrate in de-ionized water and TEM. Spectral absorption properties of CeO2 have been studied in the resulting mixture got stirred by adding a few drops of solution the wavelength range 200-800 nm from Shimadzu UV-1800 UV- of NaOH and PEG till the occurrence of precipitation. The above Vis spectrophotometer. process was carried out at room temperature and the pH value was 2.2. Antipathogens property study using CeO2. maintained at 11. Figure 1. depicts the reaction mechanism in flow Possible antipathogenic properties of CeO2 and Cu-doped chart scheme. The resultant precipitates were washed, dried and CeO2 nanoparticles were experimented using different pathogenic heated to temperature of 110° C for 12 h. The final product has (bacterial) strains. The under mentioned strains of bacteria viz., S. been taken for analysis through XRD, SEM and TEM in detail. aureus, vancomycin-resistant Enterococcus faecium, S.pyogenes, E. coli, K.pneumonia, P.aeruginosa, A.baumannii and Proteus mirabilis were commercially produced through American type culture collection and those were actually utilized under well diffusion method. Synthesised pure CeO2 and Cu-doped (1%, 3% and 5 mol%) CeO2 nanoparticles were taken in doubly de ionized water and sonicated. The strain named; S. aureus, vancomycin-resistant Enterococcus faecium, S.pyogenes, E. coli, K.pneumonia, P.aeruginosa, A.baumannii and Proteus mirabilis were cultured in nutrient broth for 24h at 37°C. Bacterial lawns were prepared using 100μl of nutrient broth culture. In each plate, the wells have been fed with 100μl of our studied powder of CeO2 and Cu-doped Figure 1. Flowchart for synthesis process pure and Cu-dopedCeO2 NPs CeO2. The observation of microbial inhibition zone in the wells using Co-precipitation technique. was confirmed after sufficient inhibition period. 3. RESULTS 3.1. X-ray diffraction pattern of CeO2 and Cu:CeO2 revealed that the average size of cerium oxide decreases after Cu nanoparticles. doping CeO2 samples, respectively. The amount of dopant (Cu %) Unit cell property and purity of crystalline phase of CeO2 increases the width of the diffraction peak increases, suggesting and Cu doped (1%, 3% and 5%) cerium oxide nanoparticles have the quality of crystalline decreases. The average crystallite size been recorded from PXRD and the pattern is depicted in Fig.2. and lattice parameters of the pure and Cu doped CeO2 nanoparticle From the Fig.2, strong peaks in the patterns were corresponds