The Experts below are selected from a list of 3507 Experts worldwide ranked by ideXlab platform
Satyanarayana Chilukuri - One of the best experts on this subject based on the ideXlab platform.
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Active and durable alkaline earth metal substituted perovskite catalysts for Dry Reforming of Methane
Applied Catalysis B: Environmental, 2018Co-Authors: Srikanth Dama, Seema R. Ghodke, Richa Bobade, Hanmant R. Gurav, Satyanarayana ChilukuriAbstract:Abstract Dry Reforming of Methane is an important process for the utilization of CO2 and to get valuable synthesis gas. Alkaline earth metal substituted MZr1-xNixO3-δ perovskites were synthesized by citrate gel method, characterized and evaluated for Dry Reforming Methane. Characterization results show that the type of alkaline earth substituted at the A site of the perovskite oxide plays an important role in terms of structure, basicity, oxygen deficiency and Ni dispersion. Calcium substituted CaZr0.8Ni0.2O3-δ catalyst shows superior activity in terms of high CH4 and CO2 conversion, while maintaining the activity even after 500 h of reaction. Mechanistic investigations were carried out using transient pulse experiments and insitu FTIR-diffuse reflectance spectroscopy. These experiments reveal that redox property and basicity play important role in activation and sustaining the Reforming reaction. Insitu FTIR measurements show that surface hydroxyl groups of the support are vital for high activity and durability of CaZr0.8Ni0.2O3-δ catalyst. XRD and TGA analysis of catalysts after reaction show the structures are retained, but peaks pertaining to coke were observed on SrZr0.8Ni0.2O3-δ and BaZr0.8Ni0.2O3-δ catalysts. On the otherhand, CaZr0.8Ni0.2O3-δ catalyst had only amorphous carbon even after 500 h of reaction. HRTEM studies revealed that SrZr0.8Ni0.2O3-δ and BaZr0.8Ni0.2O3-δ catalysts deactivated mostly due to the formation of carbon nanotubes with Ni embedded in them. Raman and XPS analysis helped in identifying types of coke precursors present on the catalysts. The investigation also illustrate that type of carbon formed depends on the basicity of perovskite oxide, metal to support interaction, Ni crystallite size, surface hydroxyl groups and oxygen defects. This study clearly demonstrated that CaZr0.8Ni0.2O3-δ is an excellent catalyst for Dry Reforming reaction with long life.
George M. Bollas - One of the best experts on this subject based on the ideXlab platform.
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Model-based analysis of bench-scale fixed-bed units for chemical-looping combustion
Chemical Engineering Journal, 2013Co-Authors: Zhiquan Zhou, Lu Han, George M. BollasAbstract:Abstract The objective of this work is to compare reaction schemes and kinetic mechanisms, and simulate the dynamic behavior of chemical-looping Reducers operating with Methane as the feed and nickel oxide as the oxygen carrier. A dynamic model for the reduction step of chemical-looping combustion in fixed-bed reactors is developed, on the basis of the same kinetic network to predict published experimental data of different fixed-bed reactors and data of a chemical-looping fixed-bed reactor operating at the University of Connecticut. Steam Reforming, water gas shift, Dry Reforming, Methane decomposition, and carbon gasification by carbon dioxide and steam are considered as reactions catalyzed by the reduced oxygen carrier. Heterogeneous reactions of the oxygen carrier encompass reactions with Methane, carbon monoxide and hydrogen. Kinetic expressions reported in the literature are compared and their parameters are estimated on the basis of experimental data of nickel-based oxygen carriers for chemical-looping combustion of Methane. Particle shrinking, molar expansion and surface area changes are accounted for in the transient plug flow reactor model. The applicability of the shrinking core and modified volumetric models, which are typically used for the description of gas–solid reactions is verified and compared against various experimental data, showing the superiority of the latter. A global mechanism and kinetic parameters that can be used to simulate CLC Reducers operating with NiO as the oxygen carrier and CH 4 as the fuel are proposed. Finally, discrepancies between published data and the model accuracy for different experimental setups are discussed.
Srikanth Dama - One of the best experts on this subject based on the ideXlab platform.
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Active and durable alkaline earth metal substituted perovskite catalysts for Dry Reforming of Methane
Applied Catalysis B: Environmental, 2018Co-Authors: Srikanth Dama, Seema R. Ghodke, Richa Bobade, Hanmant R. Gurav, Satyanarayana ChilukuriAbstract:Abstract Dry Reforming of Methane is an important process for the utilization of CO2 and to get valuable synthesis gas. Alkaline earth metal substituted MZr1-xNixO3-δ perovskites were synthesized by citrate gel method, characterized and evaluated for Dry Reforming Methane. Characterization results show that the type of alkaline earth substituted at the A site of the perovskite oxide plays an important role in terms of structure, basicity, oxygen deficiency and Ni dispersion. Calcium substituted CaZr0.8Ni0.2O3-δ catalyst shows superior activity in terms of high CH4 and CO2 conversion, while maintaining the activity even after 500 h of reaction. Mechanistic investigations were carried out using transient pulse experiments and insitu FTIR-diffuse reflectance spectroscopy. These experiments reveal that redox property and basicity play important role in activation and sustaining the Reforming reaction. Insitu FTIR measurements show that surface hydroxyl groups of the support are vital for high activity and durability of CaZr0.8Ni0.2O3-δ catalyst. XRD and TGA analysis of catalysts after reaction show the structures are retained, but peaks pertaining to coke were observed on SrZr0.8Ni0.2O3-δ and BaZr0.8Ni0.2O3-δ catalysts. On the otherhand, CaZr0.8Ni0.2O3-δ catalyst had only amorphous carbon even after 500 h of reaction. HRTEM studies revealed that SrZr0.8Ni0.2O3-δ and BaZr0.8Ni0.2O3-δ catalysts deactivated mostly due to the formation of carbon nanotubes with Ni embedded in them. Raman and XPS analysis helped in identifying types of coke precursors present on the catalysts. The investigation also illustrate that type of carbon formed depends on the basicity of perovskite oxide, metal to support interaction, Ni crystallite size, surface hydroxyl groups and oxygen defects. This study clearly demonstrated that CaZr0.8Ni0.2O3-δ is an excellent catalyst for Dry Reforming reaction with long life.
Seema R. Ghodke - One of the best experts on this subject based on the ideXlab platform.
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Active and durable alkaline earth metal substituted perovskite catalysts for Dry Reforming of Methane
Applied Catalysis B: Environmental, 2018Co-Authors: Srikanth Dama, Seema R. Ghodke, Richa Bobade, Hanmant R. Gurav, Satyanarayana ChilukuriAbstract:Abstract Dry Reforming of Methane is an important process for the utilization of CO2 and to get valuable synthesis gas. Alkaline earth metal substituted MZr1-xNixO3-δ perovskites were synthesized by citrate gel method, characterized and evaluated for Dry Reforming Methane. Characterization results show that the type of alkaline earth substituted at the A site of the perovskite oxide plays an important role in terms of structure, basicity, oxygen deficiency and Ni dispersion. Calcium substituted CaZr0.8Ni0.2O3-δ catalyst shows superior activity in terms of high CH4 and CO2 conversion, while maintaining the activity even after 500 h of reaction. Mechanistic investigations were carried out using transient pulse experiments and insitu FTIR-diffuse reflectance spectroscopy. These experiments reveal that redox property and basicity play important role in activation and sustaining the Reforming reaction. Insitu FTIR measurements show that surface hydroxyl groups of the support are vital for high activity and durability of CaZr0.8Ni0.2O3-δ catalyst. XRD and TGA analysis of catalysts after reaction show the structures are retained, but peaks pertaining to coke were observed on SrZr0.8Ni0.2O3-δ and BaZr0.8Ni0.2O3-δ catalysts. On the otherhand, CaZr0.8Ni0.2O3-δ catalyst had only amorphous carbon even after 500 h of reaction. HRTEM studies revealed that SrZr0.8Ni0.2O3-δ and BaZr0.8Ni0.2O3-δ catalysts deactivated mostly due to the formation of carbon nanotubes with Ni embedded in them. Raman and XPS analysis helped in identifying types of coke precursors present on the catalysts. The investigation also illustrate that type of carbon formed depends on the basicity of perovskite oxide, metal to support interaction, Ni crystallite size, surface hydroxyl groups and oxygen defects. This study clearly demonstrated that CaZr0.8Ni0.2O3-δ is an excellent catalyst for Dry Reforming reaction with long life.
Richa Bobade - One of the best experts on this subject based on the ideXlab platform.
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Active and durable alkaline earth metal substituted perovskite catalysts for Dry Reforming of Methane
Applied Catalysis B: Environmental, 2018Co-Authors: Srikanth Dama, Seema R. Ghodke, Richa Bobade, Hanmant R. Gurav, Satyanarayana ChilukuriAbstract:Abstract Dry Reforming of Methane is an important process for the utilization of CO2 and to get valuable synthesis gas. Alkaline earth metal substituted MZr1-xNixO3-δ perovskites were synthesized by citrate gel method, characterized and evaluated for Dry Reforming Methane. Characterization results show that the type of alkaline earth substituted at the A site of the perovskite oxide plays an important role in terms of structure, basicity, oxygen deficiency and Ni dispersion. Calcium substituted CaZr0.8Ni0.2O3-δ catalyst shows superior activity in terms of high CH4 and CO2 conversion, while maintaining the activity even after 500 h of reaction. Mechanistic investigations were carried out using transient pulse experiments and insitu FTIR-diffuse reflectance spectroscopy. These experiments reveal that redox property and basicity play important role in activation and sustaining the Reforming reaction. Insitu FTIR measurements show that surface hydroxyl groups of the support are vital for high activity and durability of CaZr0.8Ni0.2O3-δ catalyst. XRD and TGA analysis of catalysts after reaction show the structures are retained, but peaks pertaining to coke were observed on SrZr0.8Ni0.2O3-δ and BaZr0.8Ni0.2O3-δ catalysts. On the otherhand, CaZr0.8Ni0.2O3-δ catalyst had only amorphous carbon even after 500 h of reaction. HRTEM studies revealed that SrZr0.8Ni0.2O3-δ and BaZr0.8Ni0.2O3-δ catalysts deactivated mostly due to the formation of carbon nanotubes with Ni embedded in them. Raman and XPS analysis helped in identifying types of coke precursors present on the catalysts. The investigation also illustrate that type of carbon formed depends on the basicity of perovskite oxide, metal to support interaction, Ni crystallite size, surface hydroxyl groups and oxygen defects. This study clearly demonstrated that CaZr0.8Ni0.2O3-δ is an excellent catalyst for Dry Reforming reaction with long life.
