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Preparation and characterization of molybdenum sulfide supported on β-zeolites obtained from [Mo3S4(H2O)9]4+ precursor

Paper ID Volume ID Publish Year Pages File Format Full-Text
44405 46024 2006 10 PDF Available
Title
Preparation and characterization of molybdenum sulfide supported on β-zeolites obtained from [Mo3S4(H2O)9]4+ precursor
Abstract

In this paper, we report an alternative procedure of cation exchange to introduce higher amount of [Mo3S4(H2O)9]4+ in β-zeolites than as reported for various zeolites (∼2 wt.%). The parent β-zeolite (Si/Al = 13.8) was partially dealuminated with a nitric acid treatment (Si/Al = 15.0 and 18.7). The three zeolites of various acidities were used as supports. The addition of ammonia during the cation exchange procedure allowed us to double the Mo loadings (4.5 wt.%) even with the most dealuminated zeolite. The acidity of the zeolitic host was restored after exchange through a thermal treatment at 350 °C under Ar. Characterizations of the Mo/β catalysts by XRD, BET and EXAFS revealed that the structures of the zeolites and that of [Mo3S4(H2O)9]4+ were preserved during ion-exchange procedure. After the thermal treatment at 350 °C, UV–visible spectroscopy, EXAFS and TEM showed that the [Mo3IVS4(H2O)9]4+ was decomposed leading to MoIVS2 and a MoVIOx species probably grafted onto the zeolite surface. Whatever the exchange conditions, in presence or in absence of ammonia, molybdenum was mainly located on the external surface of the zeolite grains and a small fraction was inside the porosity as indicated by the TEM study.

Keywords
Catalyst preparation; Cation exchange; [Mo3S4(H2O)9]4+; Thiocomplex; Cubane; β-Zeolites; Hydrodesulfurization; Hydrotreatment; Acidity; EXAFS; XANES; TEM; UV–visible
First Page Preview
Preparation and characterization of molybdenum sulfide supported on β-zeolites obtained from [Mo3S4(H2O)9]4+ precursor
Publisher
Database: Elsevier - ScienceDirect
Journal: Applied Catalysis A: General - Volume 306, 7 June 2006, Pages 165–174
Authors
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Subjects
Physical Sciences and Engineering Chemical Engineering Catalysis