Elastomers and Composites Vol. 51, No. 1, pp. 49~55 (March 2016) Print ISSN 2092-9676/Online ISSN 2288-7725 DOI: http://dx.doi.org/10.7473/ec.2016.51.1.49 Preparation of [C 60 ]Fullerene-CoS 2 Nanocomposites and Kinetics Study for Photocatalytic Degradation of Organic Dyes Jae Jin Kim and Weon Bae Ko Department of Chemistry, Sahmyook University, Seoul 139-742, Korea (Received December 11, 2015, Revised December 22, 2015, Accepted December 31, 2015) Abstract: Nanosized cobalt disulfide (CoS 2 ) particles were synthesized with 0.08 M cobalt chloride hexahydrate (CoCl 2 6H 2 O) and 0.2 M sodium thiosulfate pentahydrate (Na 2 S 2 O 3 5H 2 O) dissolved in distilled water under microwave irradiation. [C 60 ]Fullerene-CoS 2 nanocomposites were prepared with nanosized CoS 2 particles and [C 60 ]fullerene as heated by 700 o C for 2 h in an electric furnace. X-ray diffraction (XRD), scanning electron microscopy (SEM) and transmission electron microscopy (TEM) identified the heated [C 60 ]fullerene-cos 2 nanocomposites. Heated [C 60 ]fullerene-cos 2 nanocomposites were investigated the activity of photocatalytic degradation as a catalyst in various organic dyes like acid yellow 23, methylene blue, methyl orange, and rhodamine B with ultraviolet light at 254 nm by UV-vis spectrophotometer. Keywords: nanosized CoS 2 particles, [C 60 ]fullerene, [C 60 ]fullerene-cos 2 nanocomposites, photocatalytic degradation, organic dyes Introduction Cobalt disulfide (CoS 2 ) is chalcogenide transition metal compound. 1-4 Transition metal chalcogenide compounds are plentiful and attracting researchers interest as materials for energy conversion applications. 5 According to a recent study, cobalt disulfide (CoS 2 ) is known to have higher thermal stability and electronic conductivity compared to other metal sulfides such as iron disulfide (FeS 2 ), nickel disulfide (NiS 2 ), and molybdenum disulfide (MoS 2 ). 5,6 Therefore, cobalt disulfide (CoS 2 ) of which the pyrite type structure likes cubic crystal has recently drawn substantial attention on the electrochemical and magnetic properties due to its potential application in lithium ion batteries, 1,5-8 spin-electronic devices, 6 magnetic materials, 7 supercapacitors, 1 catalysts, 1,7 and solar cells. 1,10 Also, cobalt disulfide (CoS 2 ) has a much lower solubility and higher electronic conductivity in molten electrolyte. 7 [C 60 ]Fullerene can be used widely in many fields, such as 2, 11 semiconductors, composite materials, and a photosensitizer. Additionally, [C 60 ]fullerene can react easily with free radicals and [C 60 ]fullerene is soluble in only nonpolar organic solvents, such as dichlorobenzene or toluene, etc. 12 Corresponding author E-mail: kowb@syu.ac.kr [C 60 ]Fullerene is an extremely hydrophobic molecule, a radical scavenger, excellent antioxidant, and poor solubility in organic solvents. 12 Much of the focus on [C 60 ]fullerene research has been on the development of hybrid materials and molecular dyads at the electron acceptor component. 13 One of the well-known [C 60 ]fullerene among carbon nanomaterials for photocatalytic application has band gap energy which is 1.6-1.9 ev. In this study, nanosized [C 60 ]fullerene-cos 2 composites were synthesized by a microwave irradiation. The photocatalytic activity of the composites on the degradating organic dyes such as acid yellow 23, methylene blue, methyl orange, and rhodamine B was evaluated by using an UV-vis spectrophotometer under ultraviolet light at 254 nm. The purpose of this research is to examine the kinetics for photocatalytic degradating organic dyes by nanosized [C 60 ]fullerene-cos 2 composites. Experimental 1. Chemicals [C 60 ]Fullerene was purchased for Tokyo Chemical Industry Co., LTD. Cobalt chloride hexahydrate (CoCl 2 6H 2 O) was purchased from Kojima Chemicals Co., LTD. Sodium thio-
50 Jae Jin Kim et al. / Elastomers and Composites Vol. 51, No. 1, pp. 49-55 (March 2016) sulfate pentahydrate (Na 2 S 3 O 3 5H 2 O) and organic dyes (acid yellow 23, methylene blue, methyl orange, and rhodamine B) were supplied by Sigma-Aldrich. composites confirmed with the use of transmission electron microscopy (TEM, JEM-2010, JEOL Ltd) at an acceleration voltage of 200 kv. 2. Preparation of nanosized [C 60 ]fullerene-cos 2 composites 3. Evaluation of the photocatalytic activity of nanosized [C 60 ]fullerene-cos 2 composites 0.08 M cobalt chloride hexahydrate (CoCl 2 6H 2 O) solution was added into a beaker, which contained 25 ml of distilled water. 0.2 M sodium thiosulfate pentahydrate (Na 2 S 3 O 3 5H 2 O) solution was added to the previous cobalt chloride hexahydrate (CoCl 2 6H 2 O) solution with continuous stirring for 10 min. The mixture was transferred to a 100 ml container and heated under microwave irradiation condition for 30 min. 14 The black precipitates were washed by distilled water and ethanol for several times and dried at 60 o C in vacuum oven for over night. The vessel containing the mixture of nanosized CoS 2 particles and [C 60 ]fullerene was placed into an electric furnace and heated at 700 o C under Ar gas for 2 h to synthesize [C 60 ]fullerene-cos 2 nanocomposites. The X- ray diffraction (XRD, D8 Advance, Bruker) used for determining the structure of the resulting product. The surface shape of nanosized [C 60 ]fullerene-cos 2 composites observed with a scanning electron microscopy (SEM, JSM-6510, JEOL Ltd) at an accelerating voltage of 0.5 to 30 kv. The morphology and size of the nanosized [C 60 ]fullerene-cos 2 The nanosized [C 60 ]fullerene-cos 2 composites were used as a photocatalyst to check for the degradating organic dyes like acid yellow 23, methylene blue, methyl orange, and rhodamine B. The nanosized [C 60 ]fullerene-cos 2 composites were put individually in a 10 ml vial, and then 10 ml of aqueous organic dye solution was added. An UV-lamp was irradiated on each vial with a wavelength of 254 nm. The organic dyes degraded by a photocatalyst were observed at using an UV-vis spectrophotometer. 4. Photocatalytic degradation of organic dyes and kinetics study The degradating kinetics data of acid yellow 23, methylene blue, methyl orange, and rhodamine B degraded by nanosized [C 60 ]fullerene-cos 2 composites as a photocatalyst were determined from experimental values by regression analysis of the linear curve using the software package Microsoft Office Professional plus 2010 Excel. Figure 1. XRD pattern of CoS 2 nanoparticles.
Preparation of [C60]Fullerene-CoS2 Nanocomposites and Kinetics Study for Photocatalytic Degradation of Organic Dyes 51 Figure 2. XRD pattern of heated [C60]fullerene-CoS2 nanocomposites. Results and Discussion 1. XRD analysis The nanosized CoS2 particles were analyzed by XRD (Figure 1). The diffraction peaks showed at 27.96, 32.37, 36.30, 39.81, 46.44, 55.08, 57.66, 60.30, 62.92, 75.44, 77.27 and 78.92 as a 2Θ value, were assigned to the (111), (200), (210), (211), (220), (311), (220), (230), (321), (331), (420) and (421). The nanosized [C60]fullerene-CoS2 composites were analyzed by XRD (Figure 2). Among the diffraction peak of the heated [C60]fullerene-CoS2 nanocomposites, the peaks at 10.76, 17.66, 20.78, 21.65, 26.81, and 30.60, which were assigned to the (111), (220), (311), (222), (331), and (422), were the characteristic of the [C60]fullerene. The peaks at 31.50, 35.21, 39.54, 46.98, 55.20, 57.66, 60.30, 62.92, 75.44, 77.27, and 78.92 were assigned to the (200), (210), (211), (220), (311), (220), (230), (321), (331), (420), and (421) corresponded to the nanosized CoS2 particles. Figure 3. SEM image of nanosized CoS2 particles. 2. SEM and TEM analysis The SEM image of the nanosized CoS2 particles showed that the CoS2 particles had a quasi-sphere shape (Figure 3). Figure 4. SEM image of heated [C60]fullerene-CoS2 nanocomposites.
52 Jae Jin Kim et al. / Elastomers and Composites Vol. 51, No. 1, pp. 49-55 (March 2016) Figure 5. TEM image of nanosized CoS2 particles. Figure 6. TEM image of heated [C60]fullerene-CoS2 nanocomposites. Figure 7. UV-vis spectra of photocatalytic degradation of (a) acid yellow 23, (b) methylene blue, (c) methyl orange and (d) rhodamine B using [C60]fullerene-CoS2 nanocomposites.
Preparation of [C 60 ]Fullerene-CoS 2 Nanocomposites and Kinetics Study for Photocatalytic Degradation of Organic Dyes 53 Figure 7. Continued. The SEM image of the nanosized [C 60 ]fullerene-cos 2 composites showed that the composites had a sphere like shape on the plate (Figure 4). Figure 5 and 6 are the TEM images of the nanosized CoS 2 particles and nanosized [C 60 ]fullerene- CoS 2 composites, respectively. The TEM image of the nanosized CoS 2 particles showed that the particles had a quasisphere shape and average size of 100 nm, whereas the image of the nanosized [C 60 ]fullerene-cos 2 composites showed that the CoS 2 particles were dispersed on the plate of [C 60 ]fullerene in the nanosized [C 60 ]fullerene-cos 2 composites of
54 Jae Jin Kim et al. / Elastomers and Composites Vol. 51, No. 1, pp. 49-55 (March 2016) which the average size was 200 nm. 3. UV-vis spectroscopy analysis of nanosized [C 60 ]fullerene- CoS 2 composites as a photocatalyst The organic dyes like acid yellow 23, methylene blue, methyl orange, and rhodamine B were used to confirm the photocatalytic performance using an UV-vis spectrophotometer. The reactor was placed for 30 min in a dark box in order to make the photocatalyst composite particles adsorb the possible amount of organic dyes. After adsorption in the dark condition for 30 min, the samples reached adsorption-desorption equilibrium. After the adsorption state was reached the ultraviolet light irradiation was started to make the degradation of organic dyes. Ultraviolet irradiation at 254 nm for 10 min revealed the UV-vis spectra of the photocatalytic degradation of (a) acid yellow 23, (b) methylene blue, (c) methyl orange and (d) rhodamine B with nanosized [C 60 ]fullerene-cos 2 composites in Figure 7. 4. Evaluation of kinetics study by photocatalytic degradation of various organic dyes The degradation curve of organic dyes by nanosized [C 60 ]fullerene-cos 2 composites are showing that a pseudofirst-order reaction model can be taken in examination for portraying the kinetics behavior. Figure 8 revealed that the degradation of the organic dyes followed a pseudo-first-order reaction law. According to the Langmuir-Hinshelwood equation, kinetics analysis showed that the photodecomposition rate of organic dyes generally be estimated as pseudo-first-order kinetics for degradation mechanisms. ln( C/C 0 ) = kt In which C 0 was the initial concentration of dyestuff solution and C was the concentration at measuring time t. When the concentration of photocatalyst was fixed at constantly, k was determined by slope. Here, the value of k can be as index number of catalyst efficiency. Conclusion The structure of nanosized [C 60 ]fullerene-cos 2 composites were confirmed by XRD. The diffraction peaks were showed at 10.76, 17.66, 20.78, 21.65, 26.81, and 30.60 as a 2Θ value, were assigned to the (111), (220), (311), (222), (331), and (422) due to [C 60 ]fullerene and 31.50, 35.21, 39.54, Figure 8. The kinetics of photocatalytic degradation of acid yellow 23 ( ), methylene blue ( ), methyl orange ( ) and rhodamine B (X) with [C 60 ]fullerene-cos 2 nanocomposites.
Preparation of [C 60 ]Fullerene-CoS 2 Nanocomposites and Kinetics Study for Photocatalytic Degradation of Organic Dyes 55 46.98, 55.20, 57.66, 60.30, 62.92, 75.44, 77.27 and 78.92 as a 2Θ value, were assigned to the (200), (210), (211), (220), (311), (220), (230), (321), (331), (420), and (421) corresponded to nanosized CoS 2 particles. SEM showed that the nanosized [C 60 ]fullerene-cos 2 composites were in the form of quasi-sphere like shape on the plate. TEM showed that the nanosized [C 60 ]fullerene-cos 2 composites had a spherical shape with a mean size of 200 nm. The nanosized [C 60 ]fullerene-cos 2 composites were synthesized to use as a photocatalyst for the degradation of acid yellow 23, methylene blue, methyl orange, and rhodamine B under UV-light at 254 nm. Kinetics analysis was indicated first-order reaction for the photocatalytic degradation of acid yellow 23, methylene blue, methyl orange, and rhodamine B. The following is the order of the kinetics of the photocatalytic degradating the organic dyes: methylene blue > rhodamine B > methyl orange > acid yellow 23. Acknowledgements This study was supported by Sahmyook University funding in Korea. References 1. N. Kumar, N. Raman, and A. Sundaresan, Synthesis and properties of cobalt sulfide phases: CoS 2 and Co 9 S 8, Z. Anorg. Allg. Chem., 6, 1069 (2014). 2. Z. D. Meng, L. Zhu, K. Ullah, S. Ye, Q. Sun, W. K. Jang, and W. C. Oh, Study of the photochemically generated of oxygen species by fullerene photosensitized CoS 2 nanocompounds, Mater. Res. Bull., 49, 272 (2014). 3. N. Wu, Y. B. Losovyj, D. Wisbey, K. D. Belashchenko, M. Manno, L. Wang, C. Leighton, and P. A. Dowben, The electronic band structure of CoS 2, J. Phys. Condens. Mat., 19, 156224 (2007). 4. P. J. Brown, K. U. Neumann, A. Simon, F. Ueno, and K. R. A. Ziebeck, Magnetization distribution in CoS 2 ; is it a half metallic ferromagnet?, J. Phys. Condens. Mat., 17, 1583 (2005). 5. M. S. Faber, M. A. Lukowski, Q. Ding, N. S. Kaiser, and S. Jin, Earth-abundant metal pyrites (FeS 2, CoS 2, NiS 2, and their alloys) for highly efficient hydrogen evolution and polysulfide reduction electrocatalysis, J. Phys. Chem. C, 118, 21347 (2014). 6. Q. Wang, L. Jiao, Y. Han, H. Du, W. Peng, Q. Huan, D. Song, Y. Si, Y. Wang, and H. Yuan, CoS 2 hollow spheres: fabrication and their application in lithium-ion batteries, J. Phys. Chem. C, 115, 8300 (2011). 7. M. Lei, R. Zhang, H. J. Yang, and Y. G. Wang, Synthesis of well dispersed cobalt disulfide and their photoluminescence and magnetic properties, Mater. Lett., 76, 87 (2012). 8. Q. Su, J. Xie, J. Zhang, Y. Zhong, G. Du, and B. Xu, In situ transmission electron microscopy observation of electrochemical behavior of CoS 2 in lithium-ion battery, ACS App. Mater. Interfaces, 6, 3016 (2014). 9. J. Dong, D. Li, Z. Peng, and Y. Zhou, Synthesis and electrochemical performance of cobalt disulfide, J. Solid State Electrochem., 12, 171 (2008). 10. M. S. Faber, K. Park, M. C. Acevedo, P. K. Santra, and S. Jin, Earth-abundant cobalt pyrite(cos 2 ) thin film on glass as a robust, high-performance counter electrode for quantum dotsensitized solar cells, J. Phys. Chem. Lett., 4, 1843 (2013). 11. E. Y. Zhang, and C. R. Wang, Fullerene self-assembly and supramolecular nanostructures, Curr. Opin. Colloid Interface Sci., 14, 148 (2009). 12. N. Gharbi, M. Pressac, M. Hadchouel, H. Szwarc, S. R. Wilson, and F. Moussa, [C 60 ]Fullerene is a powerful antioxidant in vivo with no acute or subacute toxicity, Nano Lett., 5, 2578 (2005). 13. S. Giordani, J. F. Colomer, F. Cattaruzza, J. Alfonsi, M. Meneghetti, M. Prato, and D. Bonifazi, Multifunctional hybrid materials composed of [C 60 ]fullerene-based functionalizedsingle-walled carbon nanotubes, Carbon, 47, 578 (2009). 14. J. Xie, S. Liu, G. Cao, T. Zhu, and X. Zhao, Self-assembly of CoS 2 /graphene nanoarchitecture by a facile one-pot route and its improved electrochemical Li-storage properties, Nano Energy, 2, 49 (2013).