The Experts below are selected from a list of 360 Experts worldwide ranked by ideXlab platform
Hongwei Xiang - One of the best experts on this subject based on the ideXlab platform.
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effect of sulfate on an iron manganese catalyst for fischer tropsch synthesis
Journal of Natural Gas Chemistry, 2007Co-Authors: Yong Yang, Haijun Wan, Zhichao Tao, Cheiighua Zhang, Hongwei XiangAbstract:Abstract The effect of sulfate on Fischer-Tropsch synthesis performance was investigated in a slurry- phase continuously stirred tank reactor (CSTR) over a Fe-Mn catalyst. The physiochemical properties of the catalyst impregnated with different levels of sulfate were characterized by N 2 physisorption, X-ray photoelectron spectroscopy (XPS), H 2 (or CO) temperature-programmed reduction (TPR), Mossbauer spectroscopy, and CO 2 temperature-programmed desorption (TPD). The characterization results indicated that the impregnated sulfate slightly decreased the BET Surface area and pore volume of the catalyst, suppressed the catalyst reduction and carburization in CO and syngas, and decreased the catalyst Surface Basicity. At the same time, the addition of small amounts of sulfate improved the activities of Fischer- Tropsch synthesis (FTS) and water gas shift (WGS), shifted the product to light hydrocarbons (C 1 –C 11 ) and suppressed the formation of heavy products (C 12+ ). Addition of SO 2 − 4 to the catalyst improved the FTS activity at a sulfur loading of 0.05–0.80 g per 100 g Fe, and S-05 catalyst gave the highest CO conversion (62.3%), and beyond this sulfur level the activity of the catalyst decreased.
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effect of manganese on an iron based fischer tropsch synthesis catalyst prepared from ferrous sulfate
Fuel, 2007Co-Authors: Yong Yang, Chenghua Zhang, Haijun Wan, Zhichao Tao, Hongwei XiangAbstract:The effects of manganese on the textural properties, bulk and Surface phase compositions, reduction/carburization behaviors and Surface Basicity of an Fe–Mn–K/SiO2 catalyst prepared from ferrous sulfate were investigated by N2 physisorption, Mossbauer spectroscopy, X-ray photoelectron spectroscopy (XPS), H2 (or CO) temperature-programmed reduction (TPR) and CO2 temperature-programmed desorption (TPD). The Fischer–Tropsch synthesis (FTS) performance of the catalysts with different contents of manganese was studied in a slurry-phase continuously stirred tank reactor. The characterization results suggested that the added manganese suppressed the crystal growth of hematite and the catalyst reduction from FeO to Fe in H2. An appropriate amount of manganese improved the FTS activity, increased the Surface Basicity and enhanced the carburization of the catalyst. However, the excessive addition of manganese retarded the catalyst carburization in CO and syngas due to the high enrichment of manganese on the catalyst Surface. At the same time, the addition of manganese suppressed the formation of CH4 and shifted the selectivity to heavy hydrocarbons (C12+).
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study of an iron manganese fischer tropsch synthesis catalyst promoted with copper
Journal of Catalysis, 2006Co-Authors: Chenghua Zhang, Yong Yang, Botao Teng, Hongyan Zheng, Hongwei XiangAbstract:Abstract The metal–silica interaction and catalytic behavior of Cu-promoted Fe–Mn–K/SiO 2 catalysts were investigated by temperature-programmed reduction/desorption (TPR/TPD), differential thermogravimetric analysis, in situ diffuse reflectance infrared Fourier transform analysis, and Mossbauer spectroscopy. The Fischer–Tropsch synthesis (FTS) performance of the catalysts with or without copper was studied in a slurry-phase continuously stirred tank reactor. The characterization results indicate that several kinds of metal oxide–silica interactions are present on Fe–Mn–K/SiO 2 catalysts with or without copper, which include iron–silica, copper–silica, and potassium–silica interactions. In addition to the well-known effect of Cu promoter on easing the reduction of iron-based FTS catalysts, it is found that Cu promoter can increase the rate of carburization, but does not vary the extent of carburization during the steady-state FTS reaction. The Basicity of the Cu and K co-promoted catalyst is greatly enhanced, as demonstrated by CO 2 -TPD results. In the FTS reaction, Cu improves the rate of catalyst activation and shortens the induction period, whereas the addition of Cu has no apparent influence on the steady-state activity of the catalyst. Promotion of Cu strongly affects hydrocarbon selectivity. The product distribution shifts to heavy hydrocarbons, and the olefin/paraffin ratio is enhanced on the catalyst due to the indirect enhancement of Surface Basicity by the copper promotion effect.
Cuong Phamhuu - One of the best experts on this subject based on the ideXlab platform.
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unraveling Surface Basicity and bulk morphology relationship on covalent triazine frameworks with unique catalytic and gas adsorption properties
Advanced Functional Materials, 2017Co-Authors: Giulia Tuci, Moritz Pilaski, Andrea Rossin, Lapo Luconi, Stefano Caporali, Cuong Phamhuu, Regina Palkovits, Giuliano GiambastianiAbstract:Activity and selectivity are key features at the basis of an efficient catalytic system for promoting the steam- and oxygen-free dehydrogenation (DDH) of ethylbenzene to styrene. The catalyst stability under severe reaction conditions, the reduction of leaching of its active sites, and their resistance to deactivation phenomena on stream are other fundamental aspects to keep in mind while synthesizing new catalytic materials for the process. Although the recent use of single-phase (doped or undoped) carbon nanomaterials has significantly contributed to improving this catalysis, the relationship between materials morphology and their chemical Surface properties still remains to be addressed. Here, a class of highly microporous, N-doped covalent triazine frameworks (CTFs) with superior activity and stability in the DDH compared to the benchmark systems of the state-of-the-art is reported. Notably, a comparative analysis of their chemico-physical properties has unveiled the role of the “chemically accessible” Surface Basicity on the catalyst passivation on stream. Finally, the unique properties of the synthesized CTFs are demonstrated by their excellent H2 storage capability and CO2 absorption that rank among the highest reported so far for related systems.
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macroscopically shaped monolith of nanodiamonds nitrogen enriched mesoporous carbon decorated sic as a superior metal free catalyst for the styrene production
Applied Catalysis B-environmental, 2017Co-Authors: Housseinou Ba, Giulia Tuci, Giuliano Giambastiani, Cuong Duongviet, Jeanmario Nhut, Lam Nguyendinh, Ovidiu Ersen, Dang Sheng Su, Cuong PhamhuuAbstract:Abstract Nanodiamonds (NDs) are recognized as a class of robust metal-free catalysts for the steam-free, direct dehydrogenation (DDH) of ethylbenzene (EB) to styrene (ST). In spite of that, some main drawbacks, such as their powdery form along with their tendency to form aggregates, limit their full exploitation at the industrial level. In this work, we describe the preparation of macroscopically shaped monoliths consisting of silicon carbide-based foams coated with a nitrogen-rich mesoporous carbon matrix (NMC) as a non-innocent glue for highly dispersed ND fillers. The NMC phase is prepared from cheap and non-toxic food-grade components and it prevents the undesired NDs agglomeration thus maximizing the reagents exposure throughout the catalytic DDH tests. Moreover, the NMC phase represents a key source of Surface Basicity capable of inhibiting the occurrence of EB cracking side reactions during the catalytic runs. As a result, the ND@NMC/SiC composite shows excellent dehydrogenation performance already at low ND loading if compared with the powdery NDs and/or the SiC-supported NDs of the state-of-the-art. Noteworthy, the ND@NMC/SiC composite presents its best catalytic performance under DDH conditions close to those used in industrial plants (reaction temperture up to 600 °C and EB concentrations up to 10 vol.%) with high ST rates (λcatal. of 9.9 mmolST gcat−1 h−1), ST selectivity over 96% and long term stability on stream.
Giuliano Giambastiani - One of the best experts on this subject based on the ideXlab platform.
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unraveling Surface Basicity and bulk morphology relationship on covalent triazine frameworks with unique catalytic and gas adsorption properties
Advanced Functional Materials, 2017Co-Authors: Giulia Tuci, Moritz Pilaski, Andrea Rossin, Lapo Luconi, Stefano Caporali, Cuong Phamhuu, Regina Palkovits, Giuliano GiambastianiAbstract:Activity and selectivity are key features at the basis of an efficient catalytic system for promoting the steam- and oxygen-free dehydrogenation (DDH) of ethylbenzene to styrene. The catalyst stability under severe reaction conditions, the reduction of leaching of its active sites, and their resistance to deactivation phenomena on stream are other fundamental aspects to keep in mind while synthesizing new catalytic materials for the process. Although the recent use of single-phase (doped or undoped) carbon nanomaterials has significantly contributed to improving this catalysis, the relationship between materials morphology and their chemical Surface properties still remains to be addressed. Here, a class of highly microporous, N-doped covalent triazine frameworks (CTFs) with superior activity and stability in the DDH compared to the benchmark systems of the state-of-the-art is reported. Notably, a comparative analysis of their chemico-physical properties has unveiled the role of the “chemically accessible” Surface Basicity on the catalyst passivation on stream. Finally, the unique properties of the synthesized CTFs are demonstrated by their excellent H2 storage capability and CO2 absorption that rank among the highest reported so far for related systems.
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macroscopically shaped monolith of nanodiamonds nitrogen enriched mesoporous carbon decorated sic as a superior metal free catalyst for the styrene production
Applied Catalysis B-environmental, 2017Co-Authors: Housseinou Ba, Giulia Tuci, Giuliano Giambastiani, Cuong Duongviet, Jeanmario Nhut, Lam Nguyendinh, Ovidiu Ersen, Dang Sheng Su, Cuong PhamhuuAbstract:Abstract Nanodiamonds (NDs) are recognized as a class of robust metal-free catalysts for the steam-free, direct dehydrogenation (DDH) of ethylbenzene (EB) to styrene (ST). In spite of that, some main drawbacks, such as their powdery form along with their tendency to form aggregates, limit their full exploitation at the industrial level. In this work, we describe the preparation of macroscopically shaped monoliths consisting of silicon carbide-based foams coated with a nitrogen-rich mesoporous carbon matrix (NMC) as a non-innocent glue for highly dispersed ND fillers. The NMC phase is prepared from cheap and non-toxic food-grade components and it prevents the undesired NDs agglomeration thus maximizing the reagents exposure throughout the catalytic DDH tests. Moreover, the NMC phase represents a key source of Surface Basicity capable of inhibiting the occurrence of EB cracking side reactions during the catalytic runs. As a result, the ND@NMC/SiC composite shows excellent dehydrogenation performance already at low ND loading if compared with the powdery NDs and/or the SiC-supported NDs of the state-of-the-art. Noteworthy, the ND@NMC/SiC composite presents its best catalytic performance under DDH conditions close to those used in industrial plants (reaction temperture up to 600 °C and EB concentrations up to 10 vol.%) with high ST rates (λcatal. of 9.9 mmolST gcat−1 h−1), ST selectivity over 96% and long term stability on stream.
Yong Yang - One of the best experts on this subject based on the ideXlab platform.
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effect of sulfate on an iron manganese catalyst for fischer tropsch synthesis
Journal of Natural Gas Chemistry, 2007Co-Authors: Yong Yang, Haijun Wan, Zhichao Tao, Cheiighua Zhang, Hongwei XiangAbstract:Abstract The effect of sulfate on Fischer-Tropsch synthesis performance was investigated in a slurry- phase continuously stirred tank reactor (CSTR) over a Fe-Mn catalyst. The physiochemical properties of the catalyst impregnated with different levels of sulfate were characterized by N 2 physisorption, X-ray photoelectron spectroscopy (XPS), H 2 (or CO) temperature-programmed reduction (TPR), Mossbauer spectroscopy, and CO 2 temperature-programmed desorption (TPD). The characterization results indicated that the impregnated sulfate slightly decreased the BET Surface area and pore volume of the catalyst, suppressed the catalyst reduction and carburization in CO and syngas, and decreased the catalyst Surface Basicity. At the same time, the addition of small amounts of sulfate improved the activities of Fischer- Tropsch synthesis (FTS) and water gas shift (WGS), shifted the product to light hydrocarbons (C 1 –C 11 ) and suppressed the formation of heavy products (C 12+ ). Addition of SO 2 − 4 to the catalyst improved the FTS activity at a sulfur loading of 0.05–0.80 g per 100 g Fe, and S-05 catalyst gave the highest CO conversion (62.3%), and beyond this sulfur level the activity of the catalyst decreased.
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effect of manganese on an iron based fischer tropsch synthesis catalyst prepared from ferrous sulfate
Fuel, 2007Co-Authors: Yong Yang, Chenghua Zhang, Haijun Wan, Zhichao Tao, Hongwei XiangAbstract:The effects of manganese on the textural properties, bulk and Surface phase compositions, reduction/carburization behaviors and Surface Basicity of an Fe–Mn–K/SiO2 catalyst prepared from ferrous sulfate were investigated by N2 physisorption, Mossbauer spectroscopy, X-ray photoelectron spectroscopy (XPS), H2 (or CO) temperature-programmed reduction (TPR) and CO2 temperature-programmed desorption (TPD). The Fischer–Tropsch synthesis (FTS) performance of the catalysts with different contents of manganese was studied in a slurry-phase continuously stirred tank reactor. The characterization results suggested that the added manganese suppressed the crystal growth of hematite and the catalyst reduction from FeO to Fe in H2. An appropriate amount of manganese improved the FTS activity, increased the Surface Basicity and enhanced the carburization of the catalyst. However, the excessive addition of manganese retarded the catalyst carburization in CO and syngas due to the high enrichment of manganese on the catalyst Surface. At the same time, the addition of manganese suppressed the formation of CH4 and shifted the selectivity to heavy hydrocarbons (C12+).
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study of an iron manganese fischer tropsch synthesis catalyst promoted with copper
Journal of Catalysis, 2006Co-Authors: Chenghua Zhang, Yong Yang, Botao Teng, Hongyan Zheng, Hongwei XiangAbstract:Abstract The metal–silica interaction and catalytic behavior of Cu-promoted Fe–Mn–K/SiO 2 catalysts were investigated by temperature-programmed reduction/desorption (TPR/TPD), differential thermogravimetric analysis, in situ diffuse reflectance infrared Fourier transform analysis, and Mossbauer spectroscopy. The Fischer–Tropsch synthesis (FTS) performance of the catalysts with or without copper was studied in a slurry-phase continuously stirred tank reactor. The characterization results indicate that several kinds of metal oxide–silica interactions are present on Fe–Mn–K/SiO 2 catalysts with or without copper, which include iron–silica, copper–silica, and potassium–silica interactions. In addition to the well-known effect of Cu promoter on easing the reduction of iron-based FTS catalysts, it is found that Cu promoter can increase the rate of carburization, but does not vary the extent of carburization during the steady-state FTS reaction. The Basicity of the Cu and K co-promoted catalyst is greatly enhanced, as demonstrated by CO 2 -TPD results. In the FTS reaction, Cu improves the rate of catalyst activation and shortens the induction period, whereas the addition of Cu has no apparent influence on the steady-state activity of the catalyst. Promotion of Cu strongly affects hydrocarbon selectivity. The product distribution shifts to heavy hydrocarbons, and the olefin/paraffin ratio is enhanced on the catalyst due to the indirect enhancement of Surface Basicity by the copper promotion effect.
Giulia Tuci - One of the best experts on this subject based on the ideXlab platform.
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unraveling Surface Basicity and bulk morphology relationship on covalent triazine frameworks with unique catalytic and gas adsorption properties
Advanced Functional Materials, 2017Co-Authors: Giulia Tuci, Moritz Pilaski, Andrea Rossin, Lapo Luconi, Stefano Caporali, Cuong Phamhuu, Regina Palkovits, Giuliano GiambastianiAbstract:Activity and selectivity are key features at the basis of an efficient catalytic system for promoting the steam- and oxygen-free dehydrogenation (DDH) of ethylbenzene to styrene. The catalyst stability under severe reaction conditions, the reduction of leaching of its active sites, and their resistance to deactivation phenomena on stream are other fundamental aspects to keep in mind while synthesizing new catalytic materials for the process. Although the recent use of single-phase (doped or undoped) carbon nanomaterials has significantly contributed to improving this catalysis, the relationship between materials morphology and their chemical Surface properties still remains to be addressed. Here, a class of highly microporous, N-doped covalent triazine frameworks (CTFs) with superior activity and stability in the DDH compared to the benchmark systems of the state-of-the-art is reported. Notably, a comparative analysis of their chemico-physical properties has unveiled the role of the “chemically accessible” Surface Basicity on the catalyst passivation on stream. Finally, the unique properties of the synthesized CTFs are demonstrated by their excellent H2 storage capability and CO2 absorption that rank among the highest reported so far for related systems.
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macroscopically shaped monolith of nanodiamonds nitrogen enriched mesoporous carbon decorated sic as a superior metal free catalyst for the styrene production
Applied Catalysis B-environmental, 2017Co-Authors: Housseinou Ba, Giulia Tuci, Giuliano Giambastiani, Cuong Duongviet, Jeanmario Nhut, Lam Nguyendinh, Ovidiu Ersen, Dang Sheng Su, Cuong PhamhuuAbstract:Abstract Nanodiamonds (NDs) are recognized as a class of robust metal-free catalysts for the steam-free, direct dehydrogenation (DDH) of ethylbenzene (EB) to styrene (ST). In spite of that, some main drawbacks, such as their powdery form along with their tendency to form aggregates, limit their full exploitation at the industrial level. In this work, we describe the preparation of macroscopically shaped monoliths consisting of silicon carbide-based foams coated with a nitrogen-rich mesoporous carbon matrix (NMC) as a non-innocent glue for highly dispersed ND fillers. The NMC phase is prepared from cheap and non-toxic food-grade components and it prevents the undesired NDs agglomeration thus maximizing the reagents exposure throughout the catalytic DDH tests. Moreover, the NMC phase represents a key source of Surface Basicity capable of inhibiting the occurrence of EB cracking side reactions during the catalytic runs. As a result, the ND@NMC/SiC composite shows excellent dehydrogenation performance already at low ND loading if compared with the powdery NDs and/or the SiC-supported NDs of the state-of-the-art. Noteworthy, the ND@NMC/SiC composite presents its best catalytic performance under DDH conditions close to those used in industrial plants (reaction temperture up to 600 °C and EB concentrations up to 10 vol.%) with high ST rates (λcatal. of 9.9 mmolST gcat−1 h−1), ST selectivity over 96% and long term stability on stream.
