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qiao_1989

新虫 (初入文坛)

应助: 0 (幼儿园)
金币: 116
帖子: 11
在线: 4.2小时
虫号: 1793350
注册: 2012-05-03

[求助] 翻译到最后一段了，求助

XGa2O3-CeO2-ZrO2 (X=0, 1, 3, 5, 7, and 9) catalysts were prepared
by a single-step sol-gel method with a variation of Ga2O3 content
(X, wt%). Based on our previous work, the ratio of cerium oxide :
zirconium oxide in the XGa2O3-CeO2-ZrO2 catalyst was fixed to
be Ce0.6Zr0.4O2. The prepared catalysts were applied to the direct synthesis
of DMC from methanol and carbon dioxide. XGa2O3-CeO2-
ZrO2 (X=1, 3, 5, 7, and 9) showed a better catalytic performance
than 0Ga2O3-CeO2-ZrO2 (Ce0.6Zr0.4O2) in the reaction due to the enhanced
acidity and basicity provided by Ga2O3. Among the catalysts
tested, 3Ga2O3-CeO2-ZrO2 catalyst showed the best catalytic
performance in the direct synthesis of DMC from methanol and
carbon dioxide. Furthermore, the amount of DMC produced over
3Ga2O3-CeO2-ZrO2 catalyst prepared by a single-step sol-gel method
was larger than that over 5Ga2O3/Ce0.6Zr0.4O2 catalyst (the best catalyst
in our previous work) prepared by an incipient wetness impregnation
method. This indicates that a single-step sol-gel method was
more efficient than an incipient wetness impregnation method in
the preparation of Ga2O3-CeO2-ZrO2 mixed metal oxide catalyst for
the reaction. NH3-TPD and CO2-TPD experiments were conducted
to investigate the effect of acidity and basicity of the catalyst on the
catalytic performance in the direct synthesis of DMC from methanol
and carbon dioxide. Experimental results revealed that the catalytic
performance of XGa2O3-CeO2-ZrO2 was closely related to both
acidity and basicity of the catalyst in this reaction. The amount of
DMC increased with increasing both acidity and basicity of the catalyst.
It is concluded that both acidity and basicity of the catalyst played
important roles in determining the catalytic performance in the direct
synthesis of DMC from methanol and carbon dioxide.

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