Catalytic function of VOx/Al2O3 for oxidative dehydrogenation of propane: support microstructure-dependent mass transfer and diffusion
Catalytic function of VOx/Al2O3 for oxidative dehydrogenation of propane: support microstructure-dependent mass transfer and diffusion
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VOx/Al2O3 对丙烷氧化脱氢的催化功能：支持微观结构依赖性传质和扩散
DOI：
10.1039/c8cy00564h
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发表时间：
2018-10
影响因子：
5
通讯作者：
Jian Lu
中科院分区：
文献类型：
--
作者：
Qun-Xing Luo;Xiao-Kang Zhang;Bo-Li Hou;Jian-Gang Chen;Chao Zhu;Zhong-Wen Liu;Zhao-Tie Liu;Jian Lu
研究了载体微观结构对VOx/Al 2 O3催化剂丙烷氧化脱氢性能的内在影响。表征结果表明，类似的氧化钒物种负载在具有不同的微观结构的Al 2 O3上，但VOx和氧化铝之间的相互作用略有修改。在这种情况下，ODHP反应中的微观结构依赖性催化功能被严格揭示。非紧凑和非单片颗粒组装成纳米带的花状形态表现出颗粒间堆积孔，这有助于严重的颗粒外扩散限制（EGDL）。具有组装为纳米片的紧凑和单片颗粒的球形形态具有颗粒间和颗粒内孔，这导致适度的EGDL。然而，这两种催化剂都没有表现出颗粒内扩散限制（IGDL）。相反，具有整体颗粒且没有二级颗粒组装的块状形态仅表现出颗粒内孔，这导致轻微的EGDL和IGDL。此外，这两种扩散干扰可以通过控制反应参数来排除。表观动力学和本征动力学的比较，以及结构-功能关系，确定EGDL可能在影响ODHP效率方面发挥重要作用。原位FT-IR研究表明，丙烷和丙烯的吸附活化是通过不同的初始中间体和转化过程进行的。前者最初涉及在反应温度下将转化为双氢和酮中间体的表面丙氧基物质。后者直接涉及π-烯丙基烷氧化物和σ-烯丙基烷氧化物物种，以及在环境温度下具有准酸酐结构的氧化钒-羧酸盐物种，在该环境温度下这些中间体易于催化燃烧。
The intrinsic effect of the support microstructure on the catalytic function of VOx/Al2O3 in the oxidative dehydrogenation of propane (ODHP) was studied. The results of characterization indicate that similar vanadia species are supported on Al2O3 with different microstructures, but that the interactions between VOx and alumina are slightly modified. In this case, the microstructure-dependent catalytic function in the ODHP reaction is rigorously revealed. The flower-like morphology with non-compact and non-monolithic particles assembled as nanoribbons exhibits inter-particle stacking pores, which contribute to a severe extra-granular diffusion limitation (EGDL). The sphere-like morphology with compact and monolithic particles assembled as nanosheets possesses both inter-particle and intra-particle pores, which lead to a moderate EGDL. However, neither catalyst exhibits an intra-granular diffusion limitation (IGDL). Conversely, the bulk-like morphology with monolithic particles and without the assembly of secondary granules only exhibits intra-particle pores, which results in a slight EGDL and IGDL. Moreover, these two disturbances of diffusion can be excluded by means of controlling the reaction parameters. A comparison of the apparent and intrinsic kinetics, together with the structure–function relationship, determines that the EGDL might play an important role in influencing the ODHP efficiency. An in situ FT-IR study shows that the adsorption-activation of propane and that of propylene proceed via different initial intermediates and transformation processes. The former initially involves surface propoxide species that will be transformed into aldehydic and ketonic intermediates at the reaction temperature. The latter directly involves π-allyl alkoxidic and σ-allyl aldehydic species, as well as vanadia-carboxylate species with a quasi-anhydride structure at ambient temperatures, at which these intermediates are prone to catalytic combustion.
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影响因子：
3.7
作者：
Zili Wu;P. Stair;S. Rugmini;S. Jackson
通讯作者：
Zili Wu;P. Stair;S. Rugmini;S. Jackson
影响因子：
4
作者：
Wachs, Israel E.
通讯作者：
Wachs, Israel E.
影响因子：
5.5
作者：
A. Corma;F. Melo;L. Sauvanaud;F. Ortega
通讯作者：
A. Corma;F. Melo;L. Sauvanaud;F. Ortega
影响因子：
4.7
作者：
F. Genser;S. Pietrzyk
通讯作者：
F. Genser;S. Pietrzyk
DOI：
10.1016/j.jcou.2016.12.005
发表时间：
2017
期刊：
Journal of CO 2 Utilization
影响因子：
--
作者：
Tehua Wang;Lin Qi;Huiyi Lu;Min Ji
通讯作者：
Tehua Wang;Lin Qi;Huiyi Lu;Min Ji