Gold supported on well-ordered ceria films: nucleation, growth and morphology in CO oxidation reaction
作者： J-L Lu , H-J Gao , S Shaikhutdinov , H-J Freund , None
DOI: 10.1007/S10562-007-9039-3
关键词:
摘要: Structure of gold nanoparticles formed by physical vapor deposition onto thin ceria films was studied scanning tunneling microscopy (STM). Gold preferentially nucleates on point defects present the terraces well-ordered, fully oxidized to a low density. The nucleation expands terrace step edges, providing large variety low-coordinated sites. Only at high coverage, Au particles grow homogeneously oxygen-terminated CeO2(111) terraces. morphology further examined STM in situ and ex elevated (up 20 mbar) pressures O2, CO, CO + O2 300 K. are found be stable ambient up 10 mbar, meanwhile sintering emerges above ∼1 mbar. Sintering particles, which mainly proceeds along edges support, is observed (1:1) mixture much lower pressure (∼10−3 mbar), thus indicating that structural stability Au/ceria catalysts intimately connected with its reactivity oxidation reaction.
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