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| 论文编号: |
122214O120120280 |
| 第一作者所在部门: |
609组 |
| 中文论文题目: |
Ga-Pd/Ga2O3 Catalysts: The Role of Gallia Polymorphs,Intermetallic Compounds, and Pretreatment Conditions on Selectivity and Stability in Different Reactions
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| 英文论文题目: |
Ga-Pd/Ga2O3 Catalysts: The Role of Gallia Polymorphs,Intermetallic Compounds, and Pretreatment Conditions on Selectivity and Stability in Different Reactions
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| 论文题目英文: |
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| 作者: |
李连地
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| 论文出处: |
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| 刊物名称: |
Chem Cat Chem
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| 年: |
2012
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| 卷: |
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| 期: |
4 |
| 页: |
1764-1775 |
| 联系作者: |
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| 收录类别: |
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| 影响因子: |
5.207
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| 摘要: |
A series of gallia-supported Pd-Ga catalysts that consist of metallic
nanoparticles on three porous polymorphs of Ga2O3 (a-, b-
, and g-Ga2O3) were synthesized by a controlled co-precipitation
of Pd and Ga. The effects of formation of Ga-Pd intermetallic
compounds (IMCs) were studied in four catalytic reactions:
methanol steam reforming, hydrogenation of acetylene,
and methanol synthesis by CO and CO2 hydrogenation reactions.
The IMC Pd2Ga forms upon reduction of a- and b-Ga2O3-
supported materials in hydrogen at temperatures of 250 and
310 8C, respectively. At higher temperatures, Ga-enrichment of
the intermetallic particles is observed, leading to formation of
Pd5Ga3 before the support itself is reduced at temperatures
above 5658C. In the case of Ga-Pd/g-Ga2O3, no information
about the metal particles could be obtained owing to their
very small size and high dispersion; however, the catalytic results
suggest that the IMC Pd2Ga also forms in this sample.Pd2Ga/gallia samples show a stable selectivity towards ethylene
in acetylene hydrogenation (75 %), which is higher than
for a monometallic Pd reference catalyst. An even higher selectivity
of 80% was observed for Pd5Ga3 supported on a-Ga2O3.
In methanol steam reforming, the Ga-Pd/Gallia catalysts
showed, in contrast to Pd/Al2O3, selectivity towards CO2 of up
to 40 %. However, higher selectivities, which have been reported
for Pd2Ga in literature, could not be reproduced in this
study, which might be a result of particle size effects. The initially
higher selectivity of the Pd5Ga3-containing samples was
not stable, suggesting superior catalytic properties for this
IMC, but that re-oxidation of Ga species and formation of
Pd2Ga occurs under reaction conditions. In methanol synthesis,
CO hydrogenation did not occur, but a considerable methanol
yield from a CO2/H2 feed was observed for Pd2Ga/a-Ga2O3. |
| 英文摘要: |
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| 外单位作者单位: |
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| 备注: |
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