TY  - JOUR
AU  - Jankovic, Bojan
AU  - Čupić, Željko
AU  - Jovanović, Dušan M.
AU  - Stanković, Miroslav
PY  - 2016
UR  - https://cer.ihtm.bg.ac.rs/handle/123456789/2662
AB  - A series of silica-supported nickel catalyst precursors was synthesized with different SiO2/Ni molar ratios. Reduction of Ni catalyst precursors with different SiO2/Ni molar ratios under a hydrogen atmosphere was investigated at different heating rates. Kinetic parameters were determined using Kissinger-Akahira-Sunose isoconversional and invariant kinetic parameter methods. It was found that for all molar ratios, the apparent activation energy (E-a) is practically constant in the conversion range of 0.20  LT = alpha  LT = 0.80. In the considered conversion range, following values of E-a were found: 134.5 kJ mol(-1) (SiO2/Ni = 0.20), 139.6 kJ mol(-1) (SiO2 /Ni = 0.80), and 128.3 kJ mol(-1) (SiO2/Ni = 1.15). It was established that the reduction of Ni catalyst precursors with different SiO2/Ni molar ratios is a complex process and can be described by the Sestak-Berggren autocatalytic model. It was found that the reaction is more Langmuir-Hinshelwood type, as hydrogen dissociates rapidly on surface nuclei and the dissociated hydrogen reacts with the Ni-O active system. It was concluded that the reduction process proceeds through bulk nucleation, which is a dominant mechanism, where three-dimensional growth of crystals with polyhedron-like morphology exists. It was found that the Ni/Si ratio decreases after the reduction process. This has been explained by low Ni and higher Si surface concentrations. It has been disclosed that Ni dispersion decreases.
PB  - Philadelphia : Taylor & Francis Inc
T2  - Chemical Engineering Communications
T1  - Kinetic Analysis of Nonisothermal Reduction of Silica-Supported Nickel Catalyst Precursors in a Hydrogen Atmosphere
VL  - 203
IS  - 2
SP  - 182
EP  - 199
DO  - 10.1080/00986445.2014.983268
ER  - 

@article{
author = "Jankovic, Bojan and Čupić, Željko and Jovanović, Dušan M. and Stanković, Miroslav",
year = "2016",
abstract = "A series of silica-supported nickel catalyst precursors was synthesized with different SiO2/Ni molar ratios. Reduction of Ni catalyst precursors with different SiO2/Ni molar ratios under a hydrogen atmosphere was investigated at different heating rates. Kinetic parameters were determined using Kissinger-Akahira-Sunose isoconversional and invariant kinetic parameter methods. It was found that for all molar ratios, the apparent activation energy (E-a) is practically constant in the conversion range of 0.20  LT = alpha  LT = 0.80. In the considered conversion range, following values of E-a were found: 134.5 kJ mol(-1) (SiO2/Ni = 0.20), 139.6 kJ mol(-1) (SiO2 /Ni = 0.80), and 128.3 kJ mol(-1) (SiO2/Ni = 1.15). It was established that the reduction of Ni catalyst precursors with different SiO2/Ni molar ratios is a complex process and can be described by the Sestak-Berggren autocatalytic model. It was found that the reaction is more Langmuir-Hinshelwood type, as hydrogen dissociates rapidly on surface nuclei and the dissociated hydrogen reacts with the Ni-O active system. It was concluded that the reduction process proceeds through bulk nucleation, which is a dominant mechanism, where three-dimensional growth of crystals with polyhedron-like morphology exists. It was found that the Ni/Si ratio decreases after the reduction process. This has been explained by low Ni and higher Si surface concentrations. It has been disclosed that Ni dispersion decreases.",
publisher = "Philadelphia : Taylor & Francis Inc",
journal = "Chemical Engineering Communications",
title = "Kinetic Analysis of Nonisothermal Reduction of Silica-Supported Nickel Catalyst Precursors in a Hydrogen Atmosphere",
volume = "203",
number = "2",
pages = "182-199",
doi = "10.1080/00986445.2014.983268"
}

Jankovic, B., Čupić, Ž., Jovanović, D. M.,& Stanković, M.. (2016). Kinetic Analysis of Nonisothermal Reduction of Silica-Supported Nickel Catalyst Precursors in a Hydrogen Atmosphere. in Chemical Engineering Communications
Philadelphia : Taylor & Francis Inc., 203(2), 182-199.
https://doi.org/10.1080/00986445.2014.983268

Jankovic B, Čupić Ž, Jovanović DM, Stanković M. Kinetic Analysis of Nonisothermal Reduction of Silica-Supported Nickel Catalyst Precursors in a Hydrogen Atmosphere. in Chemical Engineering Communications. 2016;203(2):182-199.
doi:10.1080/00986445.2014.983268 .

Jankovic, Bojan, Čupić, Željko, Jovanović, Dušan M., Stanković, Miroslav, "Kinetic Analysis of Nonisothermal Reduction of Silica-Supported Nickel Catalyst Precursors in a Hydrogen Atmosphere" in Chemical Engineering Communications, 203, no. 2 (2016):182-199,
https://doi.org/10.1080/00986445.2014.983268 . .

TY  - JOUR
AU  - Jankovic, Bojan
AU  - Čupić, Željko
AU  - Jovanović, Dušan M.
AU  - Stanković, Miroslav
PY  - 2016
UR  - https://cer.ihtm.bg.ac.rs/handle/123456789/1980
AB  - A series of silica-supported nickel catalyst precursors was synthesized with different SiO2/Ni molar ratios. Reduction of Ni catalyst precursors with different SiO2/Ni molar ratios under a hydrogen atmosphere was investigated at different heating rates. Kinetic parameters were determined using Kissinger-Akahira-Sunose isoconversional and invariant kinetic parameter methods. It was found that for all molar ratios, the apparent activation energy (E-a) is practically constant in the conversion range of 0.20  LT = alpha  LT = 0.80. In the considered conversion range, following values of E-a were found: 134.5 kJ mol(-1) (SiO2/Ni = 0.20), 139.6 kJ mol(-1) (SiO2 /Ni = 0.80), and 128.3 kJ mol(-1) (SiO2/Ni = 1.15). It was established that the reduction of Ni catalyst precursors with different SiO2/Ni molar ratios is a complex process and can be described by the Sestak-Berggren autocatalytic model. It was found that the reaction is more Langmuir-Hinshelwood type, as hydrogen dissociates rapidly on surface nuclei and the dissociated hydrogen reacts with the Ni-O active system. It was concluded that the reduction process proceeds through bulk nucleation, which is a dominant mechanism, where three-dimensional growth of crystals with polyhedron-like morphology exists. It was found that the Ni/Si ratio decreases after the reduction process. This has been explained by low Ni and higher Si surface concentrations. It has been disclosed that Ni dispersion decreases.
PB  - Taylor & Francis Inc, Philadelphia
T2  - Chemical Engineering Communications
T1  - Kinetic Analysis of Nonisothermal Reduction of Silica-Supported Nickel Catalyst Precursors in a Hydrogen Atmosphere
VL  - 203
IS  - 2
SP  - 182
EP  - 199
DO  - 10.1080/00986445.2014.983268
ER  - 

@article{
author = "Jankovic, Bojan and Čupić, Željko and Jovanović, Dušan M. and Stanković, Miroslav",
year = "2016",
abstract = "A series of silica-supported nickel catalyst precursors was synthesized with different SiO2/Ni molar ratios. Reduction of Ni catalyst precursors with different SiO2/Ni molar ratios under a hydrogen atmosphere was investigated at different heating rates. Kinetic parameters were determined using Kissinger-Akahira-Sunose isoconversional and invariant kinetic parameter methods. It was found that for all molar ratios, the apparent activation energy (E-a) is practically constant in the conversion range of 0.20  LT = alpha  LT = 0.80. In the considered conversion range, following values of E-a were found: 134.5 kJ mol(-1) (SiO2/Ni = 0.20), 139.6 kJ mol(-1) (SiO2 /Ni = 0.80), and 128.3 kJ mol(-1) (SiO2/Ni = 1.15). It was established that the reduction of Ni catalyst precursors with different SiO2/Ni molar ratios is a complex process and can be described by the Sestak-Berggren autocatalytic model. It was found that the reaction is more Langmuir-Hinshelwood type, as hydrogen dissociates rapidly on surface nuclei and the dissociated hydrogen reacts with the Ni-O active system. It was concluded that the reduction process proceeds through bulk nucleation, which is a dominant mechanism, where three-dimensional growth of crystals with polyhedron-like morphology exists. It was found that the Ni/Si ratio decreases after the reduction process. This has been explained by low Ni and higher Si surface concentrations. It has been disclosed that Ni dispersion decreases.",
publisher = "Taylor & Francis Inc, Philadelphia",
journal = "Chemical Engineering Communications",
title = "Kinetic Analysis of Nonisothermal Reduction of Silica-Supported Nickel Catalyst Precursors in a Hydrogen Atmosphere",
volume = "203",
number = "2",
pages = "182-199",
doi = "10.1080/00986445.2014.983268"
}

Jankovic, B., Čupić, Ž., Jovanović, D. M.,& Stanković, M.. (2016). Kinetic Analysis of Nonisothermal Reduction of Silica-Supported Nickel Catalyst Precursors in a Hydrogen Atmosphere. in Chemical Engineering Communications
Taylor & Francis Inc, Philadelphia., 203(2), 182-199.
https://doi.org/10.1080/00986445.2014.983268

Jankovic B, Čupić Ž, Jovanović DM, Stanković M. Kinetic Analysis of Nonisothermal Reduction of Silica-Supported Nickel Catalyst Precursors in a Hydrogen Atmosphere. in Chemical Engineering Communications. 2016;203(2):182-199.
doi:10.1080/00986445.2014.983268 .

Jankovic, Bojan, Čupić, Željko, Jovanović, Dušan M., Stanković, Miroslav, "Kinetic Analysis of Nonisothermal Reduction of Silica-Supported Nickel Catalyst Precursors in a Hydrogen Atmosphere" in Chemical Engineering Communications, 203, no. 2 (2016):182-199,
https://doi.org/10.1080/00986445.2014.983268 . .

TY  - JOUR
AU  - Jankovic, Bojan
AU  - Čupić, Željko
AU  - Jovanović, Dušan M.
PY  - 2014
UR  - https://cer.ihtm.bg.ac.rs/handle/123456789/1405
AB  - A series of silica-supported nickel catalyst precursors was synthesized with different SiO2/Ni mole ratios (0.20, 0.80 and 1.15). Non-isothermal reduction of Ni catalyst precursors was investigated by temperature-programmed reduction at four different heating rates (2, 5, 10 and 20 A degrees C min(-1)), in a hydrogen atmosphere. Kinetic parameters (E (a), A) were determined using Friedman isoconversional method. It was found that for all mole ratios, apparent activation energy is practically constant in conversion range of alpha = 30-70 %. In considered conversion range, the following values of apparent activation energy were found: E (a) = 129.5 kJ mol(-1) (SiO2/Ni = 0.20), E (a) = 133.8 kJ mol(-1) (SiO2/Ni = 0.80) and E (a) = 125.0 kJ mol(-1) (SiO2/Ni = 1.15). Using two special functions (y(alpha) and z(alpha)), the kinetic model was determined. It was established that reduction of Ni catalyst precursors with different SiO2/Ni mole ratios is a complex process and can be described by two-parameter estak-Berggren (SB) autocatalytic model. Based on established values of SB parameters for each mole ratio, the possible mechanism was discussed. It was found that for all investigated ratios, the Weibull distribution function fits very well the experimental data, in the wide range of conversions (alpha = 5-95 %). Based on obtained values of Weibull shape parameter (theta), it was found that experimentally evaluated density distribution functions of the apparent activation energies can be approximated by the unbalanced peaked normal distribution.
PB  - Springer, New York
T2  - Journal of the Iranian Chemical Society
T1  - Non-isothermal reduction of silica-supported nickel catalyst precursors in hydrogen atmosphere: a kinetic study and statistical interpretation
VL  - 11
IS  - 6
SP  - 1743
EP  - 1758
DO  - 10.1007/s13738-014-0447-1
ER  - 

@article{
author = "Jankovic, Bojan and Čupić, Željko and Jovanović, Dušan M.",
year = "2014",
abstract = "A series of silica-supported nickel catalyst precursors was synthesized with different SiO2/Ni mole ratios (0.20, 0.80 and 1.15). Non-isothermal reduction of Ni catalyst precursors was investigated by temperature-programmed reduction at four different heating rates (2, 5, 10 and 20 A degrees C min(-1)), in a hydrogen atmosphere. Kinetic parameters (E (a), A) were determined using Friedman isoconversional method. It was found that for all mole ratios, apparent activation energy is practically constant in conversion range of alpha = 30-70 %. In considered conversion range, the following values of apparent activation energy were found: E (a) = 129.5 kJ mol(-1) (SiO2/Ni = 0.20), E (a) = 133.8 kJ mol(-1) (SiO2/Ni = 0.80) and E (a) = 125.0 kJ mol(-1) (SiO2/Ni = 1.15). Using two special functions (y(alpha) and z(alpha)), the kinetic model was determined. It was established that reduction of Ni catalyst precursors with different SiO2/Ni mole ratios is a complex process and can be described by two-parameter estak-Berggren (SB) autocatalytic model. Based on established values of SB parameters for each mole ratio, the possible mechanism was discussed. It was found that for all investigated ratios, the Weibull distribution function fits very well the experimental data, in the wide range of conversions (alpha = 5-95 %). Based on obtained values of Weibull shape parameter (theta), it was found that experimentally evaluated density distribution functions of the apparent activation energies can be approximated by the unbalanced peaked normal distribution.",
publisher = "Springer, New York",
journal = "Journal of the Iranian Chemical Society",
title = "Non-isothermal reduction of silica-supported nickel catalyst precursors in hydrogen atmosphere: a kinetic study and statistical interpretation",
volume = "11",
number = "6",
pages = "1743-1758",
doi = "10.1007/s13738-014-0447-1"
}

Jankovic, B., Čupić, Ž.,& Jovanović, D. M.. (2014). Non-isothermal reduction of silica-supported nickel catalyst precursors in hydrogen atmosphere: a kinetic study and statistical interpretation. in Journal of the Iranian Chemical Society
Springer, New York., 11(6), 1743-1758.
https://doi.org/10.1007/s13738-014-0447-1

Jankovic B, Čupić Ž, Jovanović DM. Non-isothermal reduction of silica-supported nickel catalyst precursors in hydrogen atmosphere: a kinetic study and statistical interpretation. in Journal of the Iranian Chemical Society. 2014;11(6):1743-1758.
doi:10.1007/s13738-014-0447-1 .

Jankovic, Bojan, Čupić, Željko, Jovanović, Dušan M., "Non-isothermal reduction of silica-supported nickel catalyst precursors in hydrogen atmosphere: a kinetic study and statistical interpretation" in Journal of the Iranian Chemical Society, 11, no. 6 (2014):1743-1758,
https://doi.org/10.1007/s13738-014-0447-1 . .

TY  - JOUR
AU  - Jankovic, Bojan
AU  - Smiciklas, Ivana
AU  - Stajić-Trošić, Jasna
AU  - Antonovic, Dusan
PY  - 2013
UR  - https://cer.ihtm.bg.ac.rs/handle/123456789/1178
AB  - Thermal characterization and kinetic analysis of non-isothermal decomposition process of Bauxite red mud were carried out using thermogravimetry (TG), derivative thermogravimetry (DTG), differential scanning calorimetry (DSC), differential thermal analysis (DTA) and Fourier transform infrared spectroscopy (FTIR). It was found that the investigated decomposition was a complex heterogeneous process, which included two main decomposition stages and one sub-stage. The overall decomposition process consisted of the series of parallel and competitive reactions, which originated from the decomposition of various chemical species and solid-state transformations. This behavior was confirmed by the appearance of different forms of density distribution functions of apparent activation energy values. Furthermore, the conversion range of 0.10  LT = alpha  LT = 0.30, with a constant value of the apparent activation energy (146.4 kJ mol(-1)) for the second stage of the overall process, belongs to calcite decomposition, which takes place through a two-dimensional diffusion mechanism.
PB  - Elsevier
T2  - International Journal of Mineral Processing
T1  - Thermal characterization and kinetic analysis of non-isothermal decomposition process of Bauxite red mud. Estimation of density distribution function of the apparent activation energy
VL  - 123
SP  - 46
EP  - 59
DO  - 10.1016/j.minpro.2013.05.003
ER  - 

@article{
author = "Jankovic, Bojan and Smiciklas, Ivana and Stajić-Trošić, Jasna and Antonovic, Dusan",
year = "2013",
abstract = "Thermal characterization and kinetic analysis of non-isothermal decomposition process of Bauxite red mud were carried out using thermogravimetry (TG), derivative thermogravimetry (DTG), differential scanning calorimetry (DSC), differential thermal analysis (DTA) and Fourier transform infrared spectroscopy (FTIR). It was found that the investigated decomposition was a complex heterogeneous process, which included two main decomposition stages and one sub-stage. The overall decomposition process consisted of the series of parallel and competitive reactions, which originated from the decomposition of various chemical species and solid-state transformations. This behavior was confirmed by the appearance of different forms of density distribution functions of apparent activation energy values. Furthermore, the conversion range of 0.10  LT = alpha  LT = 0.30, with a constant value of the apparent activation energy (146.4 kJ mol(-1)) for the second stage of the overall process, belongs to calcite decomposition, which takes place through a two-dimensional diffusion mechanism.",
publisher = "Elsevier",
journal = "International Journal of Mineral Processing",
title = "Thermal characterization and kinetic analysis of non-isothermal decomposition process of Bauxite red mud. Estimation of density distribution function of the apparent activation energy",
volume = "123",
pages = "46-59",
doi = "10.1016/j.minpro.2013.05.003"
}

Jankovic, B., Smiciklas, I., Stajić-Trošić, J.,& Antonovic, D.. (2013). Thermal characterization and kinetic analysis of non-isothermal decomposition process of Bauxite red mud. Estimation of density distribution function of the apparent activation energy. in International Journal of Mineral Processing
Elsevier., 123, 46-59.
https://doi.org/10.1016/j.minpro.2013.05.003

Jankovic B, Smiciklas I, Stajić-Trošić J, Antonovic D. Thermal characterization and kinetic analysis of non-isothermal decomposition process of Bauxite red mud. Estimation of density distribution function of the apparent activation energy. in International Journal of Mineral Processing. 2013;123:46-59.
doi:10.1016/j.minpro.2013.05.003 .

Jankovic, Bojan, Smiciklas, Ivana, Stajić-Trošić, Jasna, Antonovic, Dusan, "Thermal characterization and kinetic analysis of non-isothermal decomposition process of Bauxite red mud. Estimation of density distribution function of the apparent activation energy" in International Journal of Mineral Processing, 123 (2013):46-59,
https://doi.org/10.1016/j.minpro.2013.05.003 . .