View More View Less
  • 1 Department of Inorganic and Analytical Chemistry, West Pomeranian University of Technology, Al. Piastow 42, Szczecin 71-065, Poland
Open access

Cross Mark

Abstract

The subsolidus phase relations of the ternary system CoO–In2O3–V2O5 were investigated by differential thermal analysis and X-ray diffraction techniques. It has been shown that the system consists of seven subsidiary systems in which three solid phases coexist in equilibrium. The melting temperatures of these subsystems have also been determined.

Abstract

The subsolidus phase relations of the ternary system CoO–In2O3–V2O5 were investigated by differential thermal analysis and X-ray diffraction techniques. It has been shown that the system consists of seven subsidiary systems in which three solid phases coexist in equilibrium. The melting temperatures of these subsystems have also been determined.

Introduction

The general aim of the studies is the search for new phases showing properties of cognitive and prospective practical interest. Cobalt metal and its compounds have found a wide range of applications in electrode materials, magnetic materials, chemical catalyst and battery [13]. Also indium compounds, in particular indium(III) orthovanadate(V) has been widely used in different branches of industry. InVO4 has been used as an auxiliary material for production of electrodes in cells of different types [4] and as a photocatalyst [5]. Interesting catalytic properties of divalent metal vanadates(V) [6, 7], including cobalt(II) vanadates(V) [1, 3] have been known for many years. It has been established that the catalytic properties of such compounds are related to the presence of isolated VO4 tetrahedrons in them [6, 7]. This finding has prompted us to undertake a comprehensive study of CoO–In2O3–V2O5 system.

Two versions of the CoO–V2O5 system are known, differing only in the range of stability of the compounds present in the systems and parameters of the eutectic points [8, 9]. As follows from the two diagrams, in the system CoO–V2O5 there are three cobalt(II) vanadates(V), i.e. CoV2O6, Co2V2O7 and Co3V2O8 [8, 9]. Also known is the phase diagram of In2O3–V2O5 system [10] in which in solid state In2O3 and V2O5 make only one compound InVO4 [10]. No phase diagram of CoO–In2O3 and no information on the phases forming in the reaction between the oxides CoO and In2O3 have been found in the available literature. Only one paper has been come across reporting on formation of a compound in the ternary system CoO–In2O3–V2O5. Previously, the work has studied the reactivity of Co2V2O7 towards InVO4 in the solid phase and have proved the formation of a new phase of the formula Co2InV3O11 [11]. This compound undergoes incongruent melting at 960 °C, and the solid product of melting is InVO4 [11]. The aim of this study was to find out whether in the ternary system CoO–In2O3–V2O5, any other compound, besides Co2InV3O11, is formed with involvement of all three oxides and to investigate the phase relations in the system studied.

Experimental

The reagents used in the study came from the following sources

  • —V2O5, pure for analysis, made by Riedel-de Haën, Germany
  • —In2O3, pure for analysis, made by Aldrich, Germany
  • —CoCO3, pure for analysis, Aldrich, Germany

The carefully weighted portions of the reagents were homogenised by milling using agate mortar and heated in the air atmosphere at a few stages until reaching a state of equilibrium. After each stage of heating, the composition of the samples was checked by XRD. The programme of heating (temperatures and duration) was different for individual samples and depended on the composition of initial mixtures.

After the final stage of heating the samples were slowly cooled down to ambient temperature (together with the furnace), and then they were ground and subjected to DTA and XRD measurements. The samples were then heated once again for 24 h at the temperature of the last stage of synthesis and after this time they were rapidly cooled down to room temperature. They were ground once again and studied by DTA and XRD methods. This procedure permitted determination of the types of phases formed in the system studied and the temperature ranges of their co-existence in the solid state [1214].

DTA measurements were performed on a Metler Toledo 851e apparatus with the samples of 65 mg each placed in quartz crucibles. Measurements were performed in nitrogen atmosphere and at temperatures from the range 500–1,500 °C, at the heating rate of 10°/min.

The phases forming in the samples were identified on the basis of XRD patterns, recorded on a DRON—3 diffractometer, working with CoKα radiation and Fe filter, and the data from PDF cards [15] and from [11]. Interpretation of XRD patterns was performed with the use of the Program Packing for Powder Diffraction (DHN/PDS).

Results and discussion

The study began with checking the formation of spinel phases in the CoO–In2O3 system. For this purpose five mixtures were made of the CoCO3/In2O3 molar ratio of 3:1, 2:1, 1:1, 1:2, and 1:3. The samples were heated in the following cycles: at 650 °C(12 h), 750 °C(12 h), 850 °C(12 h), 950 °C(12 h) and additionally at 1,000 °C(3 × 12 h) and 1,100 °C(8 × 7 h). After the last stage of heating the diffractograms of the samples still gave evidence of the presence of Co3O4 and In2O3 oxides. Co3O4 oxide forms as a result of oxidation of cobalt(II) oxide formed on decomposition of CoCO3, [16]. The next set of samples was made of the following CoCO3/In2O3 molar ratios: 2:1, 1:1, 1:2 and they were heated in argon atmosphere at 900 °C for 48 h, then cooled down to room temperature under continuous flow of argon. The diffractograms of these samples did not reveal any new diffraction lines besides those characteristic of the oxides CoO, Co3O4, and In2O3. The next objective was to establish the phase equilibrium diagram of the subsolidus are of the ternary oxide system CoO–In2O3–V2O5, which was started from investigation of phase relations along the CoO–InVO4 line. Table 1 presents the compositions of initial mixtures, conditions of their heating and XRD results obtained for the samples after the last stage of heating.

Table 1

The composition, the heating conditions, and the kind of phases detected after the last heating stage in the samples from the system CoO–InVO4

NoContents/mol%/The heating temperature and timeThe composition of the sample in an equilibrium state
CoOInVO4
110.0090.00450–550 °C/24 h + 650 °C/24 h + 750 °C/24 hInVO4, In2O3, Co3V2O8
220.0080.00800 °C/24 h + 850 °C/2 × 24 h + 900 °C/2 × 24 h
330.0070.00
440.0060.00
550.0050.00
655.0045.00
760.0040.00In2O3, Co3V2O8
866.6733.33In2O3, Co3V2O8, Co3O4
970.0030.00
1080.0020.00
1190.0010.00

XRD analysis of the samples obtained from the initial mixtures containing 90.00, 80.00, 70.00 and 66.67% mol CoO has shown the presence of three phases In2O3, Co3V2O8 and Co3O4. The presence of Co3O4 follows from the fact that cobalt(II) oxide does not exist below 900 °C because it is oxidised [17]. In the sample corresponding to the initial CoO/InVO4 molar ratio of 3:2 two phases In2O3 and Co3V2O8 were identified. The other samples formed from the initial mixtures containing 55.00, 50.00, 40.00, 30.00, 20.00, and 10.00% mol CoO, were composed of InVO4, In2O3 and Co3V2O8.

As follows from the results obtained, the system CoO–InVO4 is not a real binary system but it is an intersection of the ternary oxide system CoO–V2O5–In2O3. It has been earlier established that the intersection Co2V2O7–InVO4 of the ternary system in the subsolidus area is a real binary system in the whole concentration range of components in which Co2InV3O11 undergoes crystallisation [11]. On the basis of the data from Table 1, from the phase equilibrium diagram in the intersection Co2V2O7–InVO4 [11] and from the phase diagrams of CoO–V2O5 [9] and In2O3–V2O5 [10] it was possible to propose a preliminary division of the subsolidus area of CoO–In2O3–V2O5 into the regions corresponding to subsidiary subsystems (Fig. 1). Regarding the fact that diffractograms of the samples were taken at room temperature and taking into account that thermal decomposition of Co3O4 takes place at about 900 °C [17] it was concluded that the phase diagram represented the region corresponding to the compounds: CoO–In2O3–Co3V2O8.

Fig. 1
Fig. 1

Preliminary division of the investigated ternary CoO–In2O3–V2O5 systems into subsidiary subsystem

Citation: Journal of Thermal Analysis and Calorimetry J Therm Anal Calorim 109, 2; 10.1007/s10973-012-2223-8

The division proposed did not include the polygon whose apices corresponded to the compounds V2O5, CoV2O6, Co2V2O7, Co2InV3O11 and InVO4. In order to establish the phase relations in this polygon and to verify the predicted partial systems in the other area of the system CoO–In2O3–V2O5. The mixtures of CoCO3, V2O5 and In2O3 were prepared of the compositions chosen to represent the ranges hitherto not studied and some hypothetical partial systems comprised in the oxide systems studied. The compositions of initial mixtures from which the second series samples were obtained, the stages of heating and phases detected in the equilibrium state are given in Table 2.

Table 2

The composition, the heating stages, and the kind of phases identified after the final heating stage of selected samples lying within the binary or ternary subsystems

NoContents/mol%/The heating temperature and timeThe phase composition of the sample in an equilibrium state
CoOIn2O3V2O5
120.0015.0065.00500 °C/12 h + 550 °C/12 h + 590 °C/2 × 12 h + 600 °C/2 × 12 h + 610 °C/12 hInVO4, N-CoV2O6, V2O5
237.0013.0050.00
325.0025.0050.00500 °C/12 h + 550 °C/12 h + 600 °C/12 h + 700 °C/2 × 12 hInVO4, N-CoV2O6
440.0015.0045.00N-CoV2O6, InVO4, Co2InV3O11
530.0025.0045.00
650.005.0045.00N-CoV2O6, Co2InV3O11
735.0015.0050.00
855.005.0040.00N-CoV2O6, Co2V2O7, Co2InV3O11
961.002.0037.00
1061.005.0034.00500 °C/12 h + 550 °C/12 h + 600 °C/12 h + 700 °C/2 × 12 h + 750 °C/2 × 12 hCo3V2O8, Co2InV3O11, Co2V2O7
1165.003.0032.00
1265.005.0030.00500 °C/12 h + 550 °C/12 h + 650 °C/12 h + 750 °C/2 × 12 h + 850 °C/12 h + 900 °C/2 × 12 hCo2InV3O11, Co3V2O8
1350.0015.0035.00Co2InV3O11, InVO4, Co3V2O8
1460.0010.0030.00Co3V2O8, InVO4
1565.0010.0025.00Co3V2O8, InVO4, In2O3
1630.0045.0025.00

In order to find out the melting points of the binary and ternary systems forming in the ternary oxide system CoO–In2O3–V2O5, all samples were subjected to DTA analysis. Figure 2 presents selected DTA curves recorded for the samples representing partial binary and ternary systems of the main system studied. The melting points of the mixtures of phases were determined as the temperatures of the beginning of the first endothermic effects not corresponding to polymorphous transformations, detected on DTA curves. Figure 2a presents the DTA curve of the sample from CoO–In2O3–Co3V2O8 system. The first endothermic effect was recorded at 865 °C and interpreted as corresponding to decomposition of Co3O4 to CoO [17]. The second endothermic effect on this DTA curve beginning at 1160 °C, probably corresponds to the melting point of the ternary mixture.

Fig. 2
Fig. 2

DTA curves of selected samples at representing equilibrium: a subsidiary system CoO–Co3V2O8–In2O3, b binary system Co3V2O8–In2O3, c subsidiary system Co3V2O8–In2O3–InVO4, d binary system Co3V2O8–InVO4, e subsidiary system Co3V2O8–Co2InV3O11–InVO4, f subsidiary system Co3V2O8–Co2V2O7–Co2InV3O11, g binary system Co3V2O8–Co2InV3O11, h subsidiary system Co2V2O7–Co2InV3O11–CoV2O6, i binary system CoV2O6–Co2InV3O11, j subsidiary system CoV2O6–Co2InV3O11–InVO4, k binary system CoV2O6–InVO4 and l subsidiary system CoV2O6–V2O5–InVO4

Citation: Journal of Thermal Analysis and Calorimetry J Therm Anal Calorim 109, 2; 10.1007/s10973-012-2223-8

On the basis of the results obtained and literature data [911], the phase diagram of the subsolidus area of the ternary oxide system CoO–In2O3–V2O5 was proposed, Fig. 3. The same figure also shows the melting points of the mixtures of phases at equilibrium and representing the partial systems and the intersections standing for the conjugation lines, i.e., the real binary intersections.

Fig. 3
Fig. 3

A division of the component concentration triangle of the system CoO–In2O3–V2O5 into partial subsystems and the melting temperatures of the subsidiary systems and binary systems

Citation: Journal of Thermal Analysis and Calorimetry J Therm Anal Calorim 109, 2; 10.1007/s10973-012-2223-8

According to the phase diagram presented in Fig. 3, seven partial systems can be distinguished in the CoO–In2O3–V2O5 system, and in each of them three solid phases coexist. The partial systems were identified as follows.

  1. CoO–In2O3–Co3V2O8
  2. Co3V2O8–In2O3–InVO4
  3. Co3V2O8–InVO4–Co2InV3O11
  4. Co3V2O8–Co2V2O7–Co2InV3O11
  5. Co2V2O7–Co2InV3O11–CoV2O6
  6. CoV2O6–Co2InV3O11–InVO4
  7. CoV2O6–InVO4–V2O5

Conclusions

As a result of a solid state reaction in the binary system CoO–In2O3 no phases are formed. In the ternary system CoO–In2O3–V2O5 only one compound of the formula Co2InV3O11 is formed with the involvement of all three oxides. On the basis of the measurements performed the phase equilibrium diagram has been proposed for the ternary system CoO–In2O3–V2O5 in the subsolidus area. It has been found that seven partial systems can be distinguished in the main system studied.

References

  • 1. Cowin, PI, Lan, R, Petit, ChTG, Zhang, L, Tao, S 2011 Conductivity and stability of cobalt pyrovanadate. J Alloys Compd 50:41174121 .

  • 2. Wilczkowska, E, Krawczyk, K, Petryk, J, Sobczak, JW, Kaszkur, Z 2010 Direct nitrous oxide decomposition with a cobalt oxide catalyst. Appl Catal A 389:165172 .

    • Crossref
    • Search Google Scholar
    • Export Citation
  • 3. El-Shobaky, GA, El-Mohsen, A, Turky, M 2000 Catalytic decomposition of H2O2 on Co3O4 doped with MgO and V2O5. Colloids Surf A 170:161172 .

    • Crossref
    • Search Google Scholar
    • Export Citation
  • 4. Xiao, G, Wang, X, Li, D, Fu, X 2008 InVO4-sensitized TiO2 photocatalysis for efficient air purification with visible light. J Photochem Photobiol A Chem 193:213221 .

    • Crossref
    • Search Google Scholar
    • Export Citation
  • 5. Enache, CS, Lioyd, D, Damen, MR, Schoonman, J R van de Krol 2009 Photo-electrochemical properties of thin-film InVO4 photoanodes: the role of deep donor state. J Phys Chem C 113:1935119360 .

    • Crossref
    • Search Google Scholar
    • Export Citation
  • 6. Charr, MA, Patel, D, King, MC, Kung, HH 1987 Selective oxidative dehydrogenation of butane over V–Mg–O catalysts. J Catal 105:483498 .

    • Crossref
    • Search Google Scholar
    • Export Citation
  • 7. Pless, JD, Bardin, BB, Kim, H-S, Ko, D, Smith, MT, Hammond, RR, Stair, PC, Poeppelmeier, KR 2004 Catalytic oxidative dehydrogenation of propane over Mg–V/Mo oxides. J Catal 223:419431 .

    • Crossref
    • Search Google Scholar
    • Export Citation
  • 8. Brisi, C 1957 The systems nickel oxide—vanadic anhydride and cobaltous oxide—vanadic anhydride. Ann Chim (Roma) 47:806816.

  • 9. Fotiev AA , Slobodin BV, Khodos Ya M. Vanadaty: sostav, sintez, strukturam svoistva. Izd Nauka Moskwa. 1988.

  • 10. Touboul, M, Melighit, K 1994 Synthesis by “chimie douce” and characterization of indium vanadates. Eur J Solid State Inorg Chem 31:151161.

    • Search Google Scholar
    • Export Citation
  • 11. Bosacka, M 2007 The synthesis and selected properties of Co2InV3O11. J Therm Anal Cal 88:4346 .

  • 12. Blonska-Tabero, A 2009 Subsolidus area of the system CdO–V2O5–Fe2O3. Cent Eur J Chem 7 2 252258 .

  • 13. Filipek, E, Piz, M 2010 The reactivity of SbVO5 with T-Nb2O5 in solid state in air. J Therm Anal Cal 101:447453 .

  • 14. Tabero, P 2010 Formation and properties of new Al8V10W16O85 and Fe8−xAlxV10W16O85 phases with the M-Nb2O5 structure. J Therm Anal Cal 101:561566 .

    • Crossref
    • Search Google Scholar
    • Export Citation
  • 15. Powder Difraktion File, International Center for Diffraction Data, Swarthmore (USA), File Nos.: 06-0416, 09-0387, 09-402, 09-418, 11-0692, 33-0628, 37-0352, 38-0090, 38-0252.

    • Search Google Scholar
    • Export Citation
  • 16. Blonska-Tabero, A 2007 Phase relations in the CoO–V2O5–Fe2O3 system in subsolidus area. J Therm Anal Cal 88:201205 .

  • 17. Shaheen, WM, Selim, MM 2001 Thermal characterization and catalytic properties of the ZnO–Co3O4/Al2O3 system. Int J Inorg Mater 3:417425 .

    • Crossref
    • Search Google Scholar
    • Export Citation
  • 1. Cowin, PI, Lan, R, Petit, ChTG, Zhang, L, Tao, S 2011 Conductivity and stability of cobalt pyrovanadate. J Alloys Compd 50:41174121 .

  • 2. Wilczkowska, E, Krawczyk, K, Petryk, J, Sobczak, JW, Kaszkur, Z 2010 Direct nitrous oxide decomposition with a cobalt oxide catalyst. Appl Catal A 389:165172 .

    • Crossref
    • Search Google Scholar
    • Export Citation
  • 3. El-Shobaky, GA, El-Mohsen, A, Turky, M 2000 Catalytic decomposition of H2O2 on Co3O4 doped with MgO and V2O5. Colloids Surf A 170:161172 .

    • Crossref
    • Search Google Scholar
    • Export Citation
  • 4. Xiao, G, Wang, X, Li, D, Fu, X 2008 InVO4-sensitized TiO2 photocatalysis for efficient air purification with visible light. J Photochem Photobiol A Chem 193:213221 .

    • Crossref
    • Search Google Scholar
    • Export Citation
  • 5. Enache, CS, Lioyd, D, Damen, MR, Schoonman, J R van de Krol 2009 Photo-electrochemical properties of thin-film InVO4 photoanodes: the role of deep donor state. J Phys Chem C 113:1935119360 .

    • Crossref
    • Search Google Scholar
    • Export Citation
  • 6. Charr, MA, Patel, D, King, MC, Kung, HH 1987 Selective oxidative dehydrogenation of butane over V–Mg–O catalysts. J Catal 105:483498 .

    • Crossref
    • Search Google Scholar
    • Export Citation
  • 7. Pless, JD, Bardin, BB, Kim, H-S, Ko, D, Smith, MT, Hammond, RR, Stair, PC, Poeppelmeier, KR 2004 Catalytic oxidative dehydrogenation of propane over Mg–V/Mo oxides. J Catal 223:419431 .

    • Crossref
    • Search Google Scholar
    • Export Citation
  • 8. Brisi, C 1957 The systems nickel oxide—vanadic anhydride and cobaltous oxide—vanadic anhydride. Ann Chim (Roma) 47:806816.

  • 9. Fotiev AA , Slobodin BV, Khodos Ya M. Vanadaty: sostav, sintez, strukturam svoistva. Izd Nauka Moskwa. 1988.

  • 10. Touboul, M, Melighit, K 1994 Synthesis by “chimie douce” and characterization of indium vanadates. Eur J Solid State Inorg Chem 31:151161.

    • Search Google Scholar
    • Export Citation
  • 11. Bosacka, M 2007 The synthesis and selected properties of Co2InV3O11. J Therm Anal Cal 88:4346 .

  • 12. Blonska-Tabero, A 2009 Subsolidus area of the system CdO–V2O5–Fe2O3. Cent Eur J Chem 7 2 252258 .

  • 13. Filipek, E, Piz, M 2010 The reactivity of SbVO5 with T-Nb2O5 in solid state in air. J Therm Anal Cal 101:447453 .

  • 14. Tabero, P 2010 Formation and properties of new Al8V10W16O85 and Fe8−xAlxV10W16O85 phases with the M-Nb2O5 structure. J Therm Anal Cal 101:561566 .

    • Crossref
    • Search Google Scholar
    • Export Citation
  • 15. Powder Difraktion File, International Center for Diffraction Data, Swarthmore (USA), File Nos.: 06-0416, 09-0387, 09-402, 09-418, 11-0692, 33-0628, 37-0352, 38-0090, 38-0252.

    • Search Google Scholar
    • Export Citation
  • 16. Blonska-Tabero, A 2007 Phase relations in the CoO–V2O5–Fe2O3 system in subsolidus area. J Therm Anal Cal 88:201205 .

  • 17. Shaheen, WM, Selim, MM 2001 Thermal characterization and catalytic properties of the ZnO–Co3O4/Al2O3 system. Int J Inorg Mater 3:417425 .

    • Crossref
    • Search Google Scholar
    • Export Citation