Direct oxidation of H-2 to H2O2 over Pd/CeO2 catalyst under ambient conditions: influence of halide ions

TitleDirect oxidation of H-2 to H2O2 over Pd/CeO2 catalyst under ambient conditions: influence of halide ions
Publication TypeJournal Article
Year of Publication2008
AuthorsSamanta, C, Choudhary, VR
JournalChemical Engineering Journal
Volume136
Issue2-3
Pagination126-132
Date PublishedMAR
Type of ArticleArticle
ISSN1385-8947
KeywordsBr- ions, H-2 to H2O2 oxidation, H2O2 decomposition, H2O2 hydrogenation, Pd/CeO2 catalyst
Abstract

Direct oxidation of H-2 by O-2 to H2O2 and decomposition/hydrogenation of H2O2 have been investigated over Pd/CeO2 catalyst in presence of different halide ions. All reactions were carried out in an aqueous acidic (0.03 M H3PO4) medium at room temperature (25 degrees C) and atmospheric pressure. When different halide ions were added directly to the reaction medium or incorporated in the catalyst, the activity/selectivity of Pd/CeO2 catalyst in the H-2 to H2O2 oxidation changed significantly, depending upon the nature of the halide ions. Different ammonium halides impregnated reduced Pd/CeO2 catalyst calcined under inert (flowing nitrogen) and oxidizing (static/flowing air) gaseous atmospheres revealed that bulk oxidation state of Pd and the nature of the halide ions incorporated into the catalyst cooperatively control the activity/selectivity of catalyst in H-2 to H2O2 oxidation. Both H2O2 decomposition and hydrogenation were found to affect strongly depending upon the nature of the halide ions present in the reaction medium or in the catalyst. Among the different halides, bromide was found the most effective promoter for enhancing the H2O2 yield/selectivity in H-2 to H2O2 oxidation, irrespective of the Pd oxidation state in the catalyst. (c) 2007 Elsevier B.V. All rights reserved.

DOI10.1016/j.cej.2007.03.016
Type of Journal (Indian or Foreign)Foreign
Impact Factor (IF)5.31
Divison category: 
Chemical Engineering & Process Development