23October2019

Nano-Micro Letters

Synthesis of Cobalt Chromite Nanoparticles by Thermolysis of Mixed Cr3+ and Co2+ Chelates of 2- Mercaptopyridin N-Oxide

Mohammad. Edrissi*, Ahmad Reza Keshavarz

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Nano-Micro Letters, , Volume 4, Issue 2, pp 83-89

Publication Date (Web): June 28, 2012 (Article)

DOI:10.3786/nml.v4i2.p83-89

*Corresponding author. E-mail: edrisi@aut.ac.ir

 

Abstract

 


Figure 1 (a) Termogravimetric (TGA) and (b) differential TG (DTG) curves for dried mixed complexes precursor of CoCr2O4.
Pure greenish-blue cobalt chromite (CoCr2O4) nanoparticles with narrow particle range of 4.1±1.9 nm and surface area of 78.2 m2×g-1 were synthesized through mixed chelates thermolysis of corresponding metals using 2-Mercaptopyridine N-oxide sodium salt as chelating agent. During the thermolysis procedure, high amount of gases were emitted that led to the formation of nanoparticles with high surface area. The product was characterized by TGA, DTG, XRD, TEM, SEM, LLS, BET and chemical analysis. Design of experiments was performed to fulfill the two levels L4 Taguchi design. It was found that the temperature and time of thermolysis process have significant effect on the particle size reduction. The Oxidation of trichloroethylene was carried out over CoCr2O4 nanocrystallite. Catalytic activity analysis revealed that the synthesis CoCr2O4 possesses high catalytic activity for this process.

 

Keywords

CoCr2O4; Nanoparticle; Chelates Termolysis; Taguchi experimental design; Combustion of trichloroethylene

 

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Introduction

 

Cobalt chromite is a potential industrial material. It is an insulating and normal spinel compound [1-5] and has various catalytic activity such as water gas shift reaction, combustion of halogenated hydrocarbons, alkylation of phenol, dehydrogenation and hydrogenation [6-11]. It is also used as ceramic material, heat resistant pigment [12,13], substrate for epitaxial growths [14,15], high density magnetic memory media, etc [16-18]. Cobalt chromite have been synthesized by sonochemical route [19,20], coprecipitation technique and heating Co2+ and Cr+3 ions with styrene maleic acid copolymer in DMF medium [21].

 

In this article we report a new and convenient method for preparation of fine nanoparticles of CoCr2O4 with high specific surface area using themolysis of mixed complexes of Co2+ and Cr3+ chelates with 2-Mercaptopyridine N-oxide sodium salt (MPNO-Na). The mole ratio of Co/Cr in the mixed chelate was 1:2. In this method, several parameters such as thermolysis temperature, time of thermolysis and concentration of Co2+ and Cr+3 in the initial materials affect the surface area and particle size of the metal oxide. L4 Taguchi experimental design was used to optimize the preparation conditions for the synthesis of cobalt chromite with low particle size [22]. To the best of our knowledge, there is no report about this process in the open literature.

 

Experimental

 

Materials

 

All chemicals used were AR grade and obtained from Sigma-Aldrich and used with out further purification. The starting materials were CoCl2.6H2O and CrCl3.6H2O as cobalt and chromium precursor respectively. 2-Mercaptopyridine N-oxidesodium salt (MPNO-Na) was used as chelating agent. Ammonium hydroxide was used as precipitating agent. Distilled deionized water was used in all experiments.

 

CoCr2O4 preparation

 

thermolysis method

 

The following procedure is based on the L4 Taguchi experimental design which is discussed later. Aqueous solutions of CoCl2×6H2O and CrCl3×6H2O were placed in 250 ml flask equipped with mechanical stirrer and thermometer. Then appropriate amount of MPNO-Na was added with stirring and the flask was heated up to 100°C with an IR heating lamp (the pH of solution 2-3.5). After 5 min digestion the precipitation was filtered, washed several times with distilled deionized water to remove the impurities and then calcined at different conditions. The product of thermal decomposition was the brilliant greenish-blue nano cobalt chromite. The experimental design was arranged for three factors: A (thermolysis temperature, °C), B (time of thermolysis, h) and C (coefficient of stoichiometric concentration of Co2+ and Cr+3 in the initial materials). Two levels assigned factor are shown in Table1.

 

Table 1 Factors and their experiment levels.

 

Table 1 Factors and their experiment levels.

 

Precipitation method

 

For comparison, a cobalt chromite sample was prepared with conventional co-precipitation method with following procedure: initially, aqueous solutions of CoCl2.6H2O and CrCl3.6H2O were placed in 250 ml flask equipped with mechanical stirrer and thermometer. Then precipitation was carried out by adding aqueous ammonia to the above stirred solution. The pH of solution was adjusted to about 8.9. After that, the precipitate was washed and filtered and dried at 100°C overnight. The final solid was then calcined in a flow of air from room temperature to 600°C with a heating rate of 2°C·min-1, and kept at this temperature for 3 h. The obtained powder was named as sample 6.

 

Characterization

 

An automatic C H N analyzer (CHN- Micro , Karl-kolb 267- 48) was used to analyze the cobalt and chromium chelates.Thermogravimetric (TGA) and differential TG (DTG) analyses were carried out in a Netzsch STA 409 system in a static air atmosphere at a heating rate of 10°C per minute. The XRD patterns were recorded on an X-ray diffractometer (Shimadsu XD3A) using a Cu-Kα monochromatized radiation source and a Ni filter in the range 2θ = 10o to 80o. The surface areas (BET) were determined by nitrogen adsorption at -196°C using an automated gas adsorption analyzer (The Tristar 3000, Micromeritics). The diagram of particle size distribution of sample was obtained with laser light scattering (LLS) instrument, (SEMATECH 230v, 50 Hz). Transmission electron microscopy (TEM, Ziss EM 900) and scanning electron microscopy (SEM, Philips XL30) were used to observe the size and morphology of CoCr2O4 nanoparticle. Atomic absorption spectrophotometry (Philip, U9100) was used to analyze CO2+ and Cr3+ ions in synthesized cobalt chromite. The catalytic reaction products were identified by a gas chromatograph coupled with mass spectrometry (GC-MS, TRACE GC Ultra, column THERMO TR-5MS 30 m-0.25 mm ID, quadrupole MS TRACE DSQ).

 

Catalyst evaluation

 

Removal of volatile trichloroethylene (TCE) pollutants has been known as challenging technology [23-27]. In this work combustion of TCE was carried over cobalt choromite nanoparticles. This compound is nonflammable and it is used in metal degreasing and drycleaning industries. TCE in the presence of catalyst is oxidized to CO2 according to the following reaction,

2291

 

Oxidative decomposition process was conducted in a glass-tube fixed bed reactor (I.D.=0.8 cm and Length=40 cm) at 330°C under atmospheric pressure with weight hourly space velocities (WHSV) of 60 Lg-1×h-1. The reaction feed was a mixture of 1500 ppm of TCE and 15000 ppm of H2O with balance air. The reaction products were analyzed by an on-line gas chromatograph (GC) equipped with TCD and FID.

 

Results and discussion

 

MPNO-Na reagent form insoluble stable five-membered ring chelates with Co2+ and Cr+3 ions according to following reactions:

2292

 

To confirm the formation of chelates by reactions (2 and 3), an automatic CHN analyzer was used to characterizechelates. Results of elemental microanalysis of cobalt and chromium chelates are given in Table 2. The thermal decomposition of mixed complexes in the presence of air can be formulated as follows:

2293

 

 

Table 2 Analysis of Co<sup>2+</sup> and Cr<sup>3+</sup> chelates.

 

Table 2 Analysis of Co2+ and Cr3+ chelates.

 

The thermal behavior of dried mixed complexes precursor was studied by TGA and DTG. The experimental curves are shown in Fig 1. As can be seen, Fig 1a shows that roughly there is no loss of weight up to 90°C, the loss is about 5% at 250°C. This can be related to removal of small amount of physically adsorbed water. However dramatic weight loss are observed at above 300°C and eventually the curve is leveled off around 10.6% of its initial weight at 600 °C.This loss of weight is attributed to the thermal decomposition of mixed complexes. A total theoretical weight loss of 88.84% would have been expected due to decomposition reaction (4), however, the total weight loss of 89.40 % is shown in the experimentally observed TGA curve. It is clear that experimental weight loss (89.4%) is in agreement with the theoretical value. The TGA curve of this sample is also shown in Fig 1b. The initial small peaks are due to loss of small amount of water. The major peak is due to the decomposition of mixed complexes which take place at 387°C.

 

Figure 1 (a) Termogravimetric (TGA) and (b) differential TG (DTG) curves for dried mixed complexes precursor of CoCr<sub>2</sub>O<sub>4</sub>.

 

Figure 1 (a) Termogravimetric (TGA) and (b) differential TG (DTG) curves for dried mixed complexes precursor of CoCr2O4.

 

The L4 Taguchi orthogonal array was used to study the optimum conditions for the preparation of smallest average particle size product. The L4 Taguchi array with levels assigned and responses are shown in Table 3. Figure 2 shows the XRD patterns of samples synthesized at different conditions indicated in Table 3. All samples are crystalline in nature and the peaks are well matched with diffraction patterns (JCPDS No: 780711). The average crystallite size was determined by the peak broadening method. The full width at half maximum (FWHM) for the highest peak was measured and the average crystallite size (D) was estimated using Scherrer's formula,

 

Figure 2 2 X-ray diffraction patterns of CoCr<sub>2</sub>O<sub>4</sub> samples synthesized at different conditions indicated in Table 3.

 

 

Figure 2 2 X-ray diffraction patterns of CoCr2O4 samples synthesized at different conditions indicated in Table 3.

2294

 

where λ is the wavelength of radiation , θ is the Bragge's angle, B and b are the FWHM observed for the sample and standard, respectively. Results are presented in the response column of Table 3. The experiment was carried out by random order.

 

Table 3 The L4 Taguchi design for 3 main factors at 2 levels.

 

Table 3 The L4 Taguchi design for 3 main factors at 2 levels.

 

Calculation of the average effects of factors follows,

2295

 

The optimum combination of factors A, B and C and the lowest magnitude of the performance was calculated from the following equation,

2296

Yis the grand average,A , B and C are the lower calculated responses for A, B, C factors.

2297

 

Therefor the optimum combination levels of A, B, C factors and the lowest average particle size belongs to the conditions of row 1 of Table 3 (i.e the preparation is robust ). When the thermolysis of mixed chelates was carried out at 540°C which is less than 600°C, some oxides impurity were detected in the XRD spectrum of product (No. 5 in Fig. 2). To check the optimum value obtained for the average particle size (Row 1 in Table 3) the appropriate amount of cobalt chromite (0.1 g) was dispersed in 100 ml distilled deionized water containing 0.5 g pentaerytritol as dispersing agent by vigorous stirring. As can be seen, Fig. 3 shows that the size range obtained with laser light scattering (LLS) for optimum conditions was 2.2-6.0 nm. The mean diameter of particles was obtained from size distribution curve using RTG correlator software to be 4.2 nm (the result obtained from XRD spectrum was 4.1 nm).The estimated factor effects on the response were calculated from Table 3 by using the following equation [28,29],

2298

where r is the number of experiments. Considering the absolute value of factor effects. The order of .variable effectiveness is,

 

Figure 3 LLS, mean and particle size distribution of cobalt chromite nanoparticles (particle size range of 2.2-6 nm).

 

Figure 3 LLS, mean and particle size distribution of cobalt chromite nanoparticles (particle size range of 2.2-6 nm).

 

A=2.7 (temperature of thermolysis, °C) > B=2.45(time of thermolysis, h) > C=0.4 (coefficient of stoichiometric concentration of Co2+ and Cr+3 in the initial materials). It is clear that the concentration of initial material have lowest effect on crystallite size of particles. This is maybe due to fast chemical reaction produces insoluble chelate. Furthermore the amount of thermolysed sample is low, therefore the temperature lag between inside and outside of sample for different sample size does not produce crucial effect on the particle size. The main effective factors on the particle size of product are temperature and time of thermolysis. Figure 4 shows changes in the crystallite size (responses) against the thermolysis temperature at two different thermolysis times. It is clear that, increasing the thermolysis temperature increases the crystallite size. The higher time of thermolysis (5 h) lead to bigger crystallite size. As the higher temperature causes sintering and aggregation of crystallite, therefore the crystallite size is increased significantly when the thermolysis temperature is increased from 600 to 800°C.

 

Figure 4 Response (Crystallite size: Y1, Y2, Y3, and Y4) obtained against the thermolysis temperature.

 

Figure 4 Response (Crystallite size: Y1, Y2, Y3, and Y4) obtained against the thermolysis temperature.

 

Figure 5 shows the TEM analysis of the CoCr2O4 nanoparticle obtained according to the recommended procedure (experiment 1 in Table 3). This image shows that the particles are roughly spherical having diameters in the range of 2.0-6.0 nm which agrees well with XRD and LLS results. Figure 6 shows the SEM analysis of the CoCr2O4 obtained withconventional coprecipitation method (sample 6). As can be seen, the particles diameters are in the range of 30-60 nm. It is clear that the coprecipitation method causes the agglomeration of particle during precipitation. While the thermolysis method lead to the particles in range of 2-6 nm.

 

Figure 5 The TEM image of the synthesized CoCr<sub>2</sub>O<sub>4</sub> nanoparticles.

 

Figure 5 The TEM image of the synthesized CoCr2O4 nanoparticles.

 

The specific surface area (SSA) of sample1 (Table 3) was measured based on the principle of N2 sorption. The SSA obtained was high ( 78.2 m2×g-1). This is because of the generation of high volume of gases during thermolysis process. The evolution of hot gases causes the loss of heat from the solid phase and favours formation of small particle with high porosity.

 

Figure 6 SEM image of the synthesized CoCr<sub>2</sub>O<sub>4</sub> (sample 6).

 

Figure 6 SEM image of the synthesized CoCr2O4 (sample 6).

 

To confirm the purity of CoCr2O4 about 0.2 g of sample was fused with ten times its weight of Na2O2 flux and the melt was dissolved in HNO3 [30]. After proper dilution the percentages of Co2+ and Cr3+ ions in cobalt chromite were determined by atomic absorption spectrophotometry. The average of duplicate results for each case are given in Table 4.

 

Table 4 Analysis of cobalt and chromium in synthesized CoCr<sub>2</sub>O<sub>4</sub>.

 

Table 4 Analysis of cobalt and chromium in synthesized CoCr2O4.

 

Figure 7 shows the catalytic performance for the decomposition of TCE over CoCr2O4 catalysts at 330°C and WHSV of 60 L×g-1×h-1 under steady-state conditions. As indicated in Fig. 7, CoCr2O4 nanoparticle obtained according to the recommended procedure (experiment 1 in Table 3, average particle size is 4.1 nm) showed higher conversion (97%) than sample 6 (particle size in the range of 30-60 nm) obtained with conventional co-precipitation method which gave 70% conversion. Comparison of catalytic activity and crystallite size of samples confirmed that the catalyst with smaller crystallite size gives more favorable active sites for the decomposition of TCE.

 

Figure 7 TCE conversion over CoCr<sub>2</sub>O<sub>4</sub> samples prepared by optimized thermolysis procedure (experiment 1 in Table 3) and conventional coprecipitation method (sample 6) at WHSV:60 L.g-1.h-1.

 

Figure 7 TCE conversion over CoCr2O4 samples prepared by optimized thermolysis procedure (experiment 1 in Table 3) and conventional coprecipitation method (sample 6) at WHSV:60 L.g-1.h-1.

 

Conclusion

 

A novel approach using new precursors is reported for the synthesis of cobalt chromite based on the decomposition of mixed chelates of Co2+ and Cr3+ ions with stoichiometric ratio using 2-Mercaptopyridine-N-Oxide Sodium salt as chelating agent. The characterization and the conditions for the complete conversion of mixed chelates to CoCr2O4nanocrystallite were confirmed by TGA, DTG, XRD, TEM, LLS, BET, SSA and chemical analysis. The L4 Taguchi design was implemented to optimize the experimental conditions for the preparation of CoCr2O4 nanoparticles. The main factors having significant effect on the particle size reduction were found to be time and temperature of thermolysis process. The SSA of CoCr2O4 synthesized by optimized method was effectively increased. This is because of generation and evolution of high amount of gases in the thermolysis process. The particle size of product was 4.1±1.9 nm. The lowest reported value is 10±2 nm [5]. The SSA of CoCr2O4 was found to be 78.2 m2×g-1. Furthermore CoCr2O4 nanoparticle with smaller crystallite size presented a better catalytic performance for oxidation of trichloroethylene. 

 

References

 

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[2] A. Broesevan Groenou, P. F. Bongers, and A. L. Stuyts, Mater. Sci. Eng. 3, 317 (1969).http://dx.doi.org/10.1016/0025-5416(69)90042-1

[3] Dimple P. Dutta, J. Manjanna, and A.k. Tyagi, J. Appl. Phys. 106, 043915 (2009).

[4] U. Luders, F.Sanchez andJ. Fontcuberta, Mater. Sci. Eng. B.126, 212 (2006).http://dx.doi.org/10.1016/j.mseb.2005.09.051

[5] L.Kumar, P.Mohanty, T.Shripathi andR. Chandana, Nanosci. Nanotechnol.Lett. 1, 199 (2009).http://dx.doi.org/10.1166/nnl.2009.1039

[6] A.S. Reddy, C.S.Gopinath and S. Chilukuri, J. Catal. 243, 278 (2006).http://dx.doi.org/10.1016/j.jcat.2006.07.014

[7] K.Sreekumar and S. Sugunan, Appl. Catal. A. General 230, 245 (2002).http://dx.doi.org/10.1016/S0926-860X(02)00006-6

[8] Y.L.Wang, Z.Zhou, M.J.Jia, X.M.Zhu, W.X. Zhang and D.Z. Jiang, Catal. Lett. 104, 67 (2005).http://dx.doi.org/10.1007/s10562-005-7438-x

[9] Y. Wang, P. Yang, G. Liu, L. Xu, M. Jia, W. Zhang and D. Jiang, Catal. Commun. 9, 2044 (2008).http://dx.doi.org/10.1016/j.catcom.2008.03.049

[10] M. I.Vass and V.Georgescu. Catal. Today 29, 463 (1996).http://dx.doi.org/10.1016/0920-5861(95)00321-5

[11] D.C.Kim and S. K. Ihm, Environ. Sci. Technol. 35, 222 (2001).http://dx.doi.org/10.1021/es001098k

[12] M. Zayat and D. Levy, Chem. Mater. 12, 2763 (2000).http://dx.doi.org/10.1021/cm001061z

[13] G.Hu and Y. Suzuki, Phys. Rev. Lett. 89, 276601 (2002).http://dx.doi.org/10.1103/PhysRevLett.89.276601

[14] U. Luders and F.Sanchez, J.Fontcuberta, Phys. Rev. B 70, 045403 (2004).http://dx.doi.org/10.1103/PhysRevB.70.045403

[15] U. Luders and F.Sánchez, J.Fontcuberta, Appl. Phys.A 81, 103 (2005).http://dx.doi.org/10.1007/s00339-004-3034-y

[16] E.Berkowitz, J.A.Lahut, I.S.Jacobs andL. M. Levinson, Phys. Rev. Lett. 34, 594 (1975).http://dx.doi.org/10.1103/PhysRevLett.34.594

[17] C.Nunes, C.F.Majkrzak and A.E.Berkowitz, J. Magn. Magn. Mater. 145, 343 (1995).http://dx.doi.org/10.1016/0304-8853(94)01627-5

[18] R. H. Kodama, A. E. Berkowitz, E. J. McNiff, Jr. and S. Foner, Phys. Rev. Lett. 77, 394 (1996).http://dx.doi.org/10.1103/PhysRevLett.77.394

[19] P. Dimple Dutta, J.Manjanna and A. K. Tyagi, J. Appl. Phys. 106, 043915 (2009).http://dx.doi.org/10.1063/1.3204659

[20] F.Domka, W.Zmierczak and G. Rotnicka, Surf. Technol. 23, 49 (1984).http://dx.doi.org/10.1016/0376-4583(84)90075-X

[21] S. Li, G. Zhao, H.Bi, Z.Huang, H.Lai, R.Gai and Y.Du, J. Magn. Magn. Mater. 305, 448 (2006).

[22] R. K. Roy, “Design of Experiments Using The Taguchi Approach: Design of Experiments Using the Taguchi Approach”,Wiley, P127, NY (2001).

[23] K.Ramanthan and J.Spivey, J. Combust. Sci. Tech. 63, 247 (1989).http://dx.doi.org/10.1080/00102208908947130

[24] G.Chen, G.E.Hoag, P.Chedda, F.Nadim, B.A.Woody and G. M. Dobbs, Hazard. Mater. 87, 171(2001).http://dx.doi.org/10.1016/S0304-3894(01)00263-1

[25] S.Scire, S.Minico, C.Crisafulli, C.Satriano and A. Pistone, Appl. Catal. B: Environ. 40, 43 (2003).http://dx.doi.org/10.1016/S0926-3373(02)00127-3

[26] M.Magureanu,N.B.Mandache, J.Hu, R.Richards, M.Floreaand V.I. Parvulescu, Appl. Catal. B: Environ. 76, 275 (2007).http://dx.doi.org/10.1016/j.apcatb.2007.05.030

[27] R.Gonzalez-Olmos, U. Roland, H. Toufar, F.-D. Kopinke and A. Georgi, Appl. Catal. B: Environ. 89, 356 (2009).http://dx.doi.org/10.1016/j.apcatb.2008.12.014

[28] W.P. Gardiner and G. Getting, “Experimental Design Techniques in Statistical Practice”, Horwood Publishing, P300 (1998).

[29] M.Edrissi andR. Norouzbeigi. Chin. J. Chem. 26, 1401 (2008).http://dx.doi.org/10.1002/cjoc.200890255

[30] D.A. Skoog, D.M.West and F.J.Holler, “Fundamentals of Analytical Chemistry”,Saunders College publishing, P756, (1992).

References

[1] Y. Yamasaki, S. Miyasaka, Y. Kaneko, J. P. He and T. Arima,Y. Tokura, Phys. Rev. Lett. 96, 207204 (2006).http://dx.doi.org/10.1103/PhysRevLett.96.207204

[2] A. Broesevan Groenou, P. F. Bongers, and A. L. Stuyts, Mater. Sci. Eng. 3, 317 (1969).http://dx.doi.org/10.1016/0025-5416(69)90042-1

[3] Dimple P. Dutta, J. Manjanna, and A.k. Tyagi, J. Appl. Phys. 106, 043915 (2009).

[4] U. Luders, F.Sanchez andJ. Fontcuberta, Mater. Sci. Eng. B.126, 212 (2006).http://dx.doi.org/10.1016/j.mseb.2005.09.051

[5] L.Kumar, P.Mohanty, T.Shripathi andR. Chandana, Nanosci. Nanotechnol.Lett. 1, 199 (2009).http://dx.doi.org/10.1166/nnl.2009.1039

[6] A.S. Reddy, C.S.Gopinath and S. Chilukuri, J. Catal. 243, 278 (2006).http://dx.doi.org/10.1016/j.jcat.2006.07.014

[7] K.Sreekumar and S. Sugunan, Appl. Catal. A. General 230, 245 (2002).http://dx.doi.org/10.1016/S0926-860X(02)00006-6

[8] Y.L.Wang, Z.Zhou, M.J.Jia, X.M.Zhu, W.X. Zhang and D.Z. Jiang, Catal. Lett. 104, 67 (2005).http://dx.doi.org/10.1007/s10562-005-7438-x

[9] Y. Wang, P. Yang, G. Liu, L. Xu, M. Jia, W. Zhang and D. Jiang, Catal. Commun. 9, 2044 (2008).http://dx.doi.org/10.1016/j.catcom.2008.03.049

[10] M. I.Vass and V.Georgescu. Catal. Today 29, 463 (1996).http://dx.doi.org/10.1016/0920-5861(95)00321-5

[11] D.C.Kim and S. K. Ihm, Environ. Sci. Technol. 35, 222 (2001).http://dx.doi.org/10.1021/es001098k

[12] M. Zayat and D. Levy, Chem. Mater. 12, 2763 (2000).http://dx.doi.org/10.1021/cm001061z

[13] G.Hu and Y. Suzuki, Phys. Rev. Lett. 89, 276601 (2002).http://dx.doi.org/10.1103/PhysRevLett.89.276601

[14] U. Luders and F.Sanchez, J.Fontcuberta, Phys. Rev. B 70, 045403 (2004).http://dx.doi.org/10.1103/PhysRevB.70.045403

[15] U. Luders and F.Sánchez, J.Fontcuberta, Appl. Phys.A 81, 103 (2005).http://dx.doi.org/10.1007/s00339-004-3034-y

[16] E.Berkowitz, J.A.Lahut, I.S.Jacobs andL. M. Levinson, Phys. Rev. Lett. 34, 594 (1975).http://dx.doi.org/10.1103/PhysRevLett.34.594

[17] C.Nunes, C.F.Majkrzak and A.E.Berkowitz, J. Magn. Magn. Mater. 145, 343 (1995).http://dx.doi.org/10.1016/0304-8853(94)01627-5

[18] R. H. Kodama, A. E. Berkowitz, E. J. McNiff, Jr. and S. Foner, Phys. Rev. Lett. 77, 394 (1996).http://dx.doi.org/10.1103/PhysRevLett.77.394

[19] P. Dimple Dutta, J.Manjanna and A. K. Tyagi, J. Appl. Phys. 106, 043915 (2009).http://dx.doi.org/10.1063/1.3204659

[20] F.Domka, W.Zmierczak and G. Rotnicka, Surf. Technol. 23, 49 (1984).http://dx.doi.org/10.1016/0376-4583(84)90075-X

[21] S. Li, G. Zhao, H.Bi, Z.Huang, H.Lai, R.Gai and Y.Du, J. Magn. Magn. Mater. 305, 448 (2006).

[22] R. K. Roy, “Design of Experiments Using The Taguchi Approach: Design of Experiments Using the Taguchi Approach”,Wiley, P127, NY (2001).

[23] K.Ramanthan and J.Spivey, J. Combust. Sci. Tech. 63, 247 (1989).http://dx.doi.org/10.1080/00102208908947130

[24] G.Chen, G.E.Hoag, P.Chedda, F.Nadim, B.A.Woody and G. M. Dobbs, Hazard. Mater. 87, 171(2001).http://dx.doi.org/10.1016/S0304-3894(01)00263-1

[25] S.Scire, S.Minico, C.Crisafulli, C.Satriano and A. Pistone, Appl. Catal. B: Environ. 40, 43 (2003).http://dx.doi.org/10.1016/S0926-3373(02)00127-3

[26] M.Magureanu,N.B.Mandache, J.Hu, R.Richards, M.Floreaand V.I. Parvulescu, Appl. Catal. B: Environ. 76, 275 (2007).http://dx.doi.org/10.1016/j.apcatb.2007.05.030

[27] R.Gonzalez-Olmos, U. Roland, H. Toufar, F.-D. Kopinke and A. Georgi, Appl. Catal. B: Environ. 89, 356 (2009).http://dx.doi.org/10.1016/j.apcatb.2008.12.014

[28] W.P. Gardiner and G. Getting, “Experimental Design Techniques in Statistical Practice”, Horwood Publishing, P300 (1998).

[29] M.Edrissi andR. Norouzbeigi. Chin. J. Chem. 26, 1401 (2008).http://dx.doi.org/10.1002/cjoc.200890255

[30] D.A. Skoog, D.M.West and F.J.Holler, “Fundamentals of Analytical Chemistry”,Saunders College publishing, P756, (1992).

Citation Information

Mohammad. Edrissi and Ahmad Reza Keshavarz, Synthesis of Cobalt Chromite Nanoparticles by Thermolysis of Mixed Cr3+ and Co2+ Chelates of 2- Mercaptopyridin N-Oxide. Nano-Micro Lett. 4 (2), 83-89 (2012). http://dx.doi.org/10.3786/nml.v4i2.p83-89

History

Received 10 April 2012; accepted 26 June 2012; published online 28 June 2012.

 


Additional Info

  • Type of Publishing: JOUR - Journal
  • Title:

    Synthesis of Cobalt Chromite Nanoparticles by Thermolysis of Mixed Cr3+ and Co2+ Chelates of 2- Mercaptopyridin N-Oxide

  • Author: Mohammad Edrisi, Ahmad Reza Keshavarz
  • Year: 2012
  • Volume: 4
  • Issue: 2
  • Journal Name: Nano-Micro Letters
  • Publisher: OPEN ACCESS HOUSE SCIENCE & TECHNOLOGY
  • ISSN: 2150-5551
  • URL: http://dx.doi.org/10.3786/nml.v4i2.p83-89
  • Abstract:

        Pure greenish-blue cobalt chromite (CoCr2O4) nanoparticles with narrow particle range of 4.1±1.9 nm and surface area of 78.2 m2×g-1 were synthesized through mixed chelates thermolysis of corresponding metals using 2-Mercaptopyridine N-oxide sodium salt as chelating agent. During the thermolysis procedure, high amount of gases were emitted that led to the formation of nanoparticles with high surface area. The product was characterized by TGA, DTG, XRD, TEM, SEM, LLS, BET and chemical analysis. Design of experiments was performed to fulfill the two levels L4 Taguchi design. It was found that the temperature and time of thermolysis process have significant effect on the particle size reduction. The Oxidation of trichloroethylene was carried out over CoCr2O4 nanocrystallite. Catalytic activity analysis revealed that the synthesis CoCr2O4 possesses high catalytic activity for this process.

    Keywords: CoCr2O4; Nanoparticle; Chelates Termolysis; Taguchi experimental design; Combustion of trichloroethylene

  • Publish Date: Thursday, 28 June 2012
  • Start Page: 083
  • Endpage: 089
  • DOI: 10.3786/nml.v4i2.p83-89