Senanayake Sanjaya D, Sadowski Jerzy T, Evans Jaime, Kundu Shankhamala, Agnoli Stefano, Yang Fan, Stacchiola Dario, Flege Jan I, Hrbek Jan, Rodriguez Jose A
§Facultad de Ciencias, Universidad Central de Venezuela, Caracas, 1020-A Venezuela.
∥Institute of Solid State Physics, University of Bremen, Bremen, Germany.
J Phys Chem Lett. 2012 Apr 5;3(7):839-43. doi: 10.1021/jz300159p. Epub 2012 Mar 8.
Our results indicate that small amounts of an oxide deposited on a stable metal surface can trigger a massive surface reconstruction under reaction conditions. In low-energy electron microscopy (LEEM) experiments, no reconstruction of Cu(111) is observed after chemisorbing oxygen or after reducing O/Cu(111) in a CO atmosphere. On the other hand, LEEM images taken in situ during the reduction of CeO2/CuO1-x/Cu(111) show a complex nonuniform transformation of the surface morphology. Ceria particles act as nucleation sites for the growth of copper microterraces once CuO1-x is reduced. Can this reconstructed surface be used to enhance the catalytic activity of inverse oxide/metal catalysts? Indeed, CeOx on reconstructed Cu(111) is an extremely active catalyst for the water-gas shift process (CO + H2O → H2 + CO2), with the Cu microterraces providing very efficient sites for the dissociation of water and subsequent reaction with CO.
我们的结果表明，少量沉积在稳定金属表面的氧化物在反应条件下可引发大规模的表面重构。在低能电子显微镜（LEEM）实验中，在化学吸附氧气后或在CO气氛中还原O/Cu(111)后，未观察到Cu(111)的重构。另一方面，在CeO2/CuO1-x/Cu(111)还原过程中原位拍摄的LEEM图像显示出表面形态的复杂非均匀转变。一旦CuO1-x被还原，氧化铈颗粒就作为铜微平台生长的成核位点。这种重构表面能否用于增强逆氧化物/金属催化剂的催化活性？实际上，重构的Cu(111)上的CeOx是水煤气变换过程（CO + H2O → H2 + CO2）的一种极其活跃的催化剂，铜微平台为水的解离及随后与CO的反应提供了非常有效的位点。
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