Kim, YC Park, NC Shin, JS Lee, SR Lee, YJ Moon, DJ 2024-01-21T08:03:26Z 2024-01-21T08:03:26Z 2021-09-01 2003-11-15 0920-5861 https://pubs.kist.re.kr/handle/201004/138088 Ethylene oxide is an important raw material in manufacturing processes of ethylene glycol, acrylonitrile and nonionic surfactants, etc. In general, commercial scaled ethylene oxide is synthesized over Ag catalysts. In this work, a series of alpha-Al2O3 supported Ag catalysts were prepared by several methods, i.e., precipitation, modified precipitation, water-alcohol, and micro emulsion methods. Particle sizes of the supported Ag were analyzed by TEM and XRD, and the TPD/TPR profiles were compared to investigate the state of adsorbed oxygen in view of the elucidation of the active oxygen species. The Ag particles of about 30 nm showed enhanced stability and higher activity than the particles less than 15 nm. The activities for the ethylene oxide of the catalysts prepared by water-alcohol method were higher than those of the catalysts prepared by micro emulsion method. It seems due to the larger particle sizes as well as the easier desorption of molecular oxygen from the catalysts. An unique TPD/TPR peak of the molecular oxygen was observed at about 400degreesC in the catalysts prepared by water-alcohol method. However, the desorption peaks of the molecular and the atomic oxygens were observed at about 400 and 650degreesC, respectively, in the micro emulsion prepared catalysts. (C) 2003 Elsevier B.V. All rights reserved. English ELSEVIER SCIENCE BV SILVER CATALYSTS SELECTIVITY AG(110) SIZE Partial oxidation of ethylene to ethylene oxide over nanosized Ag/alpha-Al2O3 catalysts Article 10.1016/j.cattod.2003.09.012 1 CATALYSIS TODAY, v.87, no.1-4, pp.153 - 162 CATALYSIS TODAY 87 1-4 153 162 scie scopus 000187365300020 2-s2.0-0344946480 Chemistry, Applied Chemistry, Physical Engineering, Chemical Chemistry Engineering Article; Proceedings Paper SILVER CATALYSTS SELECTIVITY AG(110) SIZE oxidation of ethylene nanosized silver catalysts preparation method TPD/TPR