A study of Cu/ZnO/Al2O3 methanol catalysts prepared by flame combustion synthesis
A study of Cu/ZnO/Al2O3 methanol catalysts prepared by flame combustion synthesis
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DOI：
10.1016/s0021-9517(03)00047-2
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发表时间：
2003-08
影响因子：
7.3
通讯作者：
J. Jensen;T. Johannessen;S. Wedel;H. Livbjerg
中科院分区：
文献类型：
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作者：
J. Jensen;T. Johannessen;S. Wedel;H. Livbjerg
研究了火焰燃烧合成Cu/ZnO/Al 2 O3催化剂在CO、CO2和H2合成甲醇反应中的催化性能。氧化物在燃烧前由与燃料和空气混合的Cu、Zn和Al的乙酰丙酮化物蒸气在预混火焰中产生。通过X射线粉末衍射、BET法测定比表面积、新型N2 O法测定还原催化剂中铜的分散度、透射电子显微镜检查和催化微反应器中催化性能的测试来检查火焰产生的粉末。火焰的低峰值温度和骤冷倾向于增加相的分散和颗粒的比表面积。三元组合物，三个二元组合物，和纯氧化物的性质进行了讨论。同时相和化学平衡的计算用于颗粒相组成的评估。比表面积从不含Al的样品的100 m2/g或略低于100 m2/g变化到纯Al 2 O 3和ZnAl 2 O 4的相应组合物的几百m2/g。还原后的铜分散度为1.8 ~ 14.1%。结果表明，Cu：Zn：Al = 45：45：10的三元催化剂具有最高的催化活性。该催化剂对热失活也具有很高的选择性和稳定性。讨论了最佳催化剂中各个催化剂组分的作用。
The flame combustion synthesis of Cu/ZnO/Al2O3catalysts for the synthesis of methanol from CO, CO2, and H2is investigated. The oxides are generated in a premixed flame from the acetylacetonate vapours of Cu, Zn, and Al mixed with the fuel and air prior to combustion. The flame-generated powder is examined by X-ray powder diffraction, determination of the specific surface area by the BET method, determination of the copper dispersion in the reduced catalyst by a novel N2O method, transmission electron microscopy, and testing of the catalytic properties in a catalytic microreactor. A low peak temperature and quench cooling of the flame tend to increase the dispersion of the phases and the specific surface area of the particles. Properties of both the ternary composition, the three binary compositions, and the pure oxides are discussed. The calculation of simultaneous phase and chemical equilibrium is used in the assessment of the phase composition of the particles. The specific surface area varies from 100 m2/g or a little below for samples without Al to several hundred m2/g for the respective compositions of pure Al2O3and ZnAl2O4. Copper dispersion after reduction varies from 1.8 to 14.1%. A ternary catalyst with the composition of Cu:Zn:Al = 45:45:10 has the highest catalytic activity of all samples tested. This catalyst is also very selective and stable toward thermal deactivation. The role of the individual catalyst components in the optimal catalyst is discussed.