Kinetic Analysis of Nonisothermal Reduction of Silica-Supported Nickel Catalyst Precursors in a Hydrogen Atmosphere
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2016
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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.
Кључне речи:
Autocatalysis / Catalyst support / Complexity / Kinetics / ReductionИзвор:
Chemical Engineering Communications, 2016, 203, 2, 182-199Издавач:
- Taylor & Francis Inc, Philadelphia
Финансирање / пројекти:
- Динамика нелинеарних физичкохемијских и биохемијских система са моделирањем и предвиђањем њихових понашања под неравнотежним условима (RS-MESTD-Basic Research (BR or ON)-172015)
- Наноструктурни функционални и композитни материјали у каталитичким и сорпционим процесима (RS-MESTD-Integrated and Interdisciplinary Research (IIR or III)-45001)
Напомена:
- The peer-reviewed version: http://cer.ihtm.bg.ac.rs/handle/123456789/2662
DOI: 10.1080/00986445.2014.983268
ISSN: 0098-6445
WoS: 000366611100004
Scopus: 2-s2.0-84947280095
Институција/група
IHTMTY - 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 . .