A “Green Route” to Propene through Selective Hydrogen Oxidation

Blank, Jan; Beckers, Jurriaan; Collignon, Paul F.; Clerc, Frédèric; Rothenberg, Gadi

doi:10.1002/chem.200601588

Cited by 48 publications

(69 citation statements)

References 32 publications

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“…The final metal concentration was calculated from the amount of precursor weighed in, corrected for the water content as determined on catalysts G1-01 to G1-18 by ICP. [11] "good" + "inactive" "good" 75-95 3 "good" + "good" "good" 75-95 4 "inactive" "bad" 0 5…”

Section: Experimental Section Materials and Instrumentationmentioning

confidence: 99%

“…[11,37] After the precursor has liquefied, the pressure was lowered and a solid mixed-metal nitrate formed. This was converted into the mixed oxide by calcining in static air at 700 8C for 5 h. The following notation is used: Gn-m, where n is the generation number and m is the catalyst number.…”

Section: Catalyst Preparation and Characterisationmentioning

confidence: 99%

“…[11,37] The formulations are synthesised and tested, and the fitness value is calculated from the obtained activity and selectivity values. From these data, a set of new catalyst formulations ("virtual catalysts"), is generated, using three steps: selection (based on the fitness value), cross-over (the exchange of genes) and mutation (a random alteration of a small amount of genes).…”

Section: Selectivity Towards Hydrogen Oxidationmentioning

confidence: 99%

“…[57] Procedure for Catalyst Synthesis Some adjustments were made to the synthesis procedure described previously. [11] The metal nitrate precursors (or chlorides or ammonium metallates, where nitrates were not available) were weighed into a crucible and placed on a heater. When liquefied, they were mixed with a spatula.…”

Section: Experimental Section Materials and Instrumentationmentioning

confidence: 99%

“…[10,11] The dehydrogenation step is performed over a conventional Pt-SnAl 2 O 3 catalyst, and the hydrogen is combusted using the oxygen of the ceria lattice (Scheme 1, left). [12] After the ceria has been reduced, the lattice oxygen vacancies are re-filled using air, creating a cyclic redox process (Scheme 1, right) and simultaneously burning off any coke.…”

Section: Introductionmentioning

confidence: 99%

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Selective Hydrogen Oxidation Catalysts via Genetic Algorithms

et al. 2008

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Solid "oxygen reservoirs," such as doped ceria, can be successfully applied in a novel process for the oxidative dehydrogenation of propane. The ceria lattice oxygen selectively burns hydrogen from the dehydrogenation mixture at 550 8C. This gives three key advantages: it shifts the dehydrogenation equilibrium to the desired product side, generates heat in situ, which aids the endothermic dehydrogenation, and simplifies product separation. We have applied a genetic algorithm to screen doped cerias for their performance in the selective hydrogen oxidation. Three generations of doped ceria catalysts (61 catalysts in total), were synthesised. Dopants were chosen from a set of 26 elements, and with a maximum of two dopants per catalyst, at five different concentrations. The catalyst performance (activity and selectivity), is expressed by a fitness value. Each generation shows a higher average fitness value. The dopant type has a large effect on the catalyst fitness. We identified six dopant atoms which lead to selective hydrogen combustion catalysts, namely bismuth (Bi), chromium (Cr), copper (Cu), potassium (K), manganese (Mn), lead (Pb) and tin (Sn) ("good" dopants). Analysis of the effect of electronegativity, ionic radius and dopant concentration shows that most elements yielding a high fitness have electronegativities ranging from 1.5-1.9. Generally, the properties of catalysts containing two dopants can be predicted from the behaviour of singly doped ones. Synergy does occur for certain copper-, iron-and platinum-containing catalysts. The addition of calcium (Ca) or magnesium (Mg) to copper-doped catalysts doubles the activity, and the selectivity of iron doped catalysts can be improved by adding chromium (Cr), manganese (Mn) or zirconium (Zr). Importantly, the doped cerias show a high stability in the redox cycling, much higher than that of supported oxides. A Cr-and Zr-doped catalyst (Ce 0.90 Cr 0.05 Zr 0.05 O 2 ) was highly selective and active over 250 redox cycles (a total of 148 h on stream), with no phase segregation or change in particle size.

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Section: Experimental Section Materials and Instrumentationmentioning

confidence: 99%

Section: Catalyst Preparation and Characterisationmentioning

confidence: 99%

Section: Selectivity Towards Hydrogen Oxidationmentioning

confidence: 99%

Section: Experimental Section Materials and Instrumentationmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Selective Hydrogen Oxidation Catalysts via Genetic Algorithms

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2016

Ceramic Membranes: New Opportunities and Practical Applications

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Bismuth‐Doped Ceria, Ce_0.90Bi_0.10O₂: A Selective and Stable Catalyst for Clean Hydrogen Combustion

Beckers¹,

Lee²,

Rothenberg³

2009

Adv Synth Catal

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Bismuth-doped cerias are successfully applied as solid "oxygen reservoirs" in the oxidative dehydrogenation of propane. The lattice oxygen of the ceria is used to selectively combust hydrogen from the dehydrogenation mixture at 550 8C. This process has three key advantages: it shifts the dehydrogenation equilibrium to the desired products side, generates heat, aiding the endothermic dehydrogenation, and simplifies product separation (water vs. hydrogen). Furthermore, the process is safer, since it uses the catalysts lattice oxygen instead of gaseous oxygen. We show here that bismuth-doped cerias are highly active and stable towards hydrogen combustion, and explore four different approaches for optimising their application in the oxidative dehydrogenation of propane: first, the addition of extra hydrogen which lowers hydrocarbon conversion by suppressing both combustion and coking; second, the addition of tin which completely inhibits coking; third, the addition of platinum which increases selectivity, but at the expense of lower activity. The best results are obtained through tuning the reaction temperature. At 400 8C, high activity and selectivity were obtained for the bismuth-doped ceria Ce 0.90 Bi 0.10 O 2 . Here, 90% of the hydrogen feed is converted at 98% selectivity. This optimal reaction temperature can be rationalised from the hydrogen and propene temperature-programmed reduction (TPR) profiles: 400 8C lies above the reduction maximum of hydrogen, yet below that of propene. That is, this temperature is sufficiently high to facilitate rapid hydrogen combustion, but low enough to prevent hydrocarbon conversion.

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A “Green Route” to Propene through Selective Hydrogen Oxidation

Cited by 48 publications

References 32 publications

Selective Hydrogen Oxidation Catalysts via Genetic Algorithms

Selective Hydrogen Oxidation Catalysts via Genetic Algorithms

Applications

Bismuth‐Doped Ceria, Ce_0.90Bi_0.10O₂: A Selective and Stable Catalyst for Clean Hydrogen Combustion

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A “Green Route” to Propene through Selective Hydrogen Oxidation

Cited by 48 publications

References 32 publications

Selective Hydrogen Oxidation Catalysts via Genetic Algorithms

Selective Hydrogen Oxidation Catalysts via Genetic Algorithms

Applications

Bismuth‐Doped Ceria, Ce0.90Bi0.10O2: A Selective and Stable Catalyst for Clean Hydrogen Combustion

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Product

Resources

About

Bismuth‐Doped Ceria, Ce_0.90Bi_0.10O₂: A Selective and Stable Catalyst for Clean Hydrogen Combustion