COUPLING BETWEEN ADJACENT CRYSTAL PLANES IN HETEROGENEOUS CATALYSIS BY PROPAGATING REACTION-DIFFUSION WAVES

被引:136
作者
GORODETSKII, V
LAUTERBACH, J
ROTERMUND, HH
BLOCK, JH
ERTL, G
机构
[1] Fritz-Haber-lnstitut der Max-Planck-Gesellschaft, D-14195 Berlin
关键词
D O I
10.1038/370276a0
中图分类号
O [数理科学和化学]; P [天文学、地球科学]; Q [生物科学]; N [自然科学总论];
学科分类号
07 ; 0710 ; 09 ;
摘要
UNDERSTANDING Of the mechanisms and kinetics of heterogeneous catalytic reactions has come largely from the study of gas-solid interactions on well defined single-crystal surfaces(1,2). But real catalysts usually consist of nanometre-sized particles on which several different crystal planes are exposed. In general, it has been assumed that their properties can be regarded as a superposition of the contributions from each individual structural element. Here we show that this assumption may be invalid, even qualitatively, in certain cases. We have studied the oxidation of hydrogen on platinum surfaces at low pressure and room temperature. On a macroscopic Pt(100) single crystal the reaction reaches a steady state with a uniform distribution of adsorbates. But on the platinum tip of a field ion microscope, on which several different crystal planes are exposed, the reaction has a very different character. The tip contains a region of the (100) plane just 40 nm in diameter, on which the reaction rate displays sustained temporal oscillations. This effect is associated with continuously changing distributions of the adsorbed species in the form of propagating waves, which are generated by coupling of reactions occurring on adjacent crystal planes. This kind of interaction between different crystal planes may exert a profound influence on the kinetics of heterogeneous catalysis.
引用
收藏
页码:276 / 279
页数:4
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