Dynamics of silver particles during ethylene epoxidation

被引：29

作者：

van Hoof, A. J. F. ^{[1
]}

van der Poll, R. C. J. ^{[1
]}

Friedrich, H. ^{[2
]}

Hensen, E. J. M. ^{[2
]}

机构：

[1] Eindhoven Univ Technol, Dept Chem Engn & Chem, Lab Inorgan Mat & Catalysis, Den Dolech 2, Eindhoven 5600 MB, Netherlands

[2] Eindhoven Univ Technol, Dept Chem Engn & Chem, Lab Phys Chem, Den Dolech 2, Eindhoven 5600 MB, Netherlands

来源：

APPLIED CATALYSIS B-ENVIRONMENTAL | 2020年 / 272卷

关键词：

ethylene oxide; silver; dynamic evolution; transmission electron microscopy; chlorine; SHAPE CHANGES; SIZE; NANOPARTICLES; CATALYSTS; OXIDATION; AG(111); SURFACE; GOLD;

D O I：

10.1016/j.apcatb.2020.118983

中图分类号：

O64 [物理化学（理论化学）、化学物理学];

学科分类号：

070304 ; 081704 ;

摘要：

Structural changes in alpha-Al2O3 supported silver particles during ethylene oxidation under industrially relevant conditions (20 bar and 225 degrees C, with and without chlorine) were investigated by quantitative TEM. Identical locations of two powder samples with average silver particle sizes of 41 nm and 127 nm were investigated in the fresh state and after 60 h of ethylene oxidation with and without chlorine. Without chlorine, silver particles were only slightly affected with a tendency for smaller (< 30 nm) particles to shrink. These silver particles even rapidly disappeared in the presence of chlorine. Particles larger than 100 nm tended to break up into smaller ones, indicative of a chlorine-induced re-dispersion process. These results confirm the dynamic nature of silver particles during the EO reaction and emphasize the role of chlorine on the observed substantial morphological changes of the active silver phase.

引用

页数：8

共 29 条

[1] Direct STM observation of surface modification and growth of AgCl islands on Ag(111) upon chlorination at room temperature [J].