Field-emission microscopic and ion bombardment studies of catalytic active sites on platinum

• Published in: Applications of surface science 1980-10, Vol.6 (2), p.93-104
• Main Authors: Kojima, Isao, Miyazaki, Eizo, Yasumori, Iwao
• Format: Article
• Language: English
• ISSN: 0378-5963; 0169-4332
• DOI: 10.1016/0378-5963(80)90137-3

Damage produced on a platinum surface by argon ion bombardment and the elimination of this damage by thermal annealing has been studied using a field emission microscope (FEM) to elucidate the structure of active sites of a platinum catalyst for the hydrogenation of acetylene. The extent of the resultant damage on the exposed surfaces of a platinum tip depends on the crystallographic orientation of planes. The most intense damage was observed along the [110] zone through (100), (311), (211) and (111) planes. The temperature region at which the surface defects on the [110] zone disappeared was found to be identical with that at which the catalytic activity of platinum decreased drastically, which suggests that surface vacancies, displaced atoms or their assemblies around the [110] zone form catalytically effective sites for hydrogenation of acetylene.