Catalytic combustion of methane over palladium supported on alumina catalysts: Evidence for reconstruction of particles
Catalytic combustion of methane over palladium supported on alumina catalysts: Evidence for reconstruction of particles
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DOI：
10.1016/0926-860x(94)80124-x
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发表时间：
1994-03
影响因子：
5.5
通讯作者：
É. Garbowski;C. Feumi-Jantou;N. Mouaddib;M. Primet
中科院分区：
文献类型：
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作者：
É. Garbowski;C. Feumi-Jantou;N. Mouaddib;M. Primet
采用纳米衍射、电子显微镜和傅里叶变换红外光谱（FT-IR）分析相结合的方法，研究了Pd/Al 2 O3固体催化剂在甲烷催化燃烧前后的物化性质。在600°C、O_2-CH_4混合气、还原性和氧化性条件下反应后，催化剂的活性显著提高，但金属相的分散度降低。新鲜的Pd/Al 2 O3样品主要表现出Pd（111）表面晶面，可以考虑与Al 2 O3（222）面的外延生长。在与两种氧-甲烷混合物反应后，Pd（200）表面晶面以Pd（111）晶面为代价而发展，通过纳米衍射以及吸附的一氧化碳的FT-IR光谱证明了Pd（200）晶面的形成。催化活性的增加与Pd（200）表面平面的存在有关。有人提出，这些后者的平面的存在下，允许从表面Pd 0到表面PdO的可逆过渡，而不会急剧变化的晶格参数。
The physicochemical properties of palladium supported on alumina solids were studied before and after the catalytic combustion of methane by combining nanodiffraction, electron microscopy and Fourier transform IR (FT-IR) analysis. The catalytic activity was strongly increased after reaction at 600°C under the O2-CH4mixture under reducing as well as under oxidizing conditions, whereas the dispersion of the metallic phase decreased. Fresh Pd/Al2O3samples exhibited mainly Pd (111) surface crystal planes and an epitaxy with the Al2O3(222) planes may be considered. After reaction with the two oxygen-methane mixtures, the Pd (200) surface crystal planes developed at the expense of the Pd (111) ones, the formation of the Pd (200) crystal planes was evidenced by nanodiffraction as well as from the FT-IR spectra of adsorbed carbon monoxide. The increase in catalytic activity was connected with the presence of the Pd (200) surface planes. It was proposed that the presence of these latter planes allows the reversible transition from surface Pd0to surface PdO without drastic changes of lattice parameters.