Detailed Characterization of Various Porous Alumina-Based Catalyst Coatings Within Microchannels and Their Testing for Methanol Steam Reforming
Detailed Characterization of Various Porous Alumina-Based Catalyst Coatings Within Microchannels and Their Testing for Methanol Steam Reforming
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DOI：
10.1205/026387603322302887
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发表时间：
2003-08
影响因子：
3.9
通讯作者：
R. Zapf;C. Becker-Willinger;K. Berresheim;H. Bolz;H. Gnaser;V. Hessel;G. Kolb;P. Löb;A.-K. Pannwitt;A. Ziogas
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文献类型：
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作者：
R. Zapf;C. Becker-Willinger;K. Berresheim;H. Bolz;H. Gnaser;V. Hessel;G. Kolb;P. Löb;A.-K. Pannwitt;A. Ziogas
对多孔氧化铝涂层的制备及其在多相气相催化中的应用进行了基础性研究，重点研究了涂层的微观结构、性能和附着力的预处理以及催化剂的测试。钢的微观结构，这是由湿化学蚀刻与氯化物溶液，在表面上显示出显着的氯含量，由于蚀刻剂。阳极氧化和热处理的微结构显着降低不希望的氯含量，这被认为是对催化剂活性的有害影响。通过机械测试证明了通过两步工艺（洗涂和湿浸渍）沉积的多孔催化剂的良好粘附性。断面轮廓精度合理可靠。以CuO/Cr2 O3/Al 2 O3体系为例，采用二次离子质谱法（西姆斯）研究了浸渍组分在涂层中横向（涂层深度）和水平方向（涂层表面）的分布。结果表明，Cr2 O3在水平和横向上均呈均匀分布，而CuO含量随涂层深度的增加而减少，并在表面形成岛状堆积物。考察了不同氧化铝载体对CuO/Cr2 O3/Al 2 O3体系甲醇水蒸气重整反应的催化活性。发现的活性与提供给反应体系的总催化剂表面积相关。
A fundamental study concerning the preparation of porous alumina washcoats in microchannels for the application in heterogeneous gas phase catalysis was performed, focusing on the pre-treatment of the microstructures, properties, and adhesion of the washcoats as well as the testing of the prepared catalysts. Steel microstructures, which are manufactured by wet-chemical etching with chloride solutions, show significant chlorine content at the surface due to the etchant. Anodic oxidation and thermal treatment of the microstructures significantly reduce the undesirable chlorine content, which is assumed to have deleterious effects on the catalyst activity. Good adhesion of the porous catalysts, deposited by a two-step process, washcoating and wet impregnation, was demonstrated by a mechanical test. Cross-sectional profile accuracy was reasonable and reliable. At the example of a CuO/Cr 2 O 3 /Al 2 O 3 system, the distribution of the impregnated components within the washcoat, in lateral (depth of the coating) and horizontal directions (at the coating's surface), was studied by secondary ion mass spectrometry (SIMS). It turned out that Cr 2 O 3 was homogeneously distributed both in horizontal and lateral direction, whereas the content of CuO decreased with the washcoat depth and islands of accumulated material on the surface were formed. The activity of the CuO/Cr 2 O 3 /Al 2 O 3 system was investigated using different alumina carriers for methanol steam reforming. The activity found was correlated with the total catalyst surface area offered to the reaction system.