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Title: On the structural differences between alumina-supported CoMoS type I and alumina-, silica, and carbon-supported CoMoS type II phases studied by XAFS, MES, and XPS

Abstract

In this study the local structure of the Mo and Co promoter atoms in CoMoS type I and II on alumina, and CoMoS type II on various supports is compared using in situ XAFS spectroscopy as the main technique with XPS and MES in a supporting role. In the CoMoS phase the Co atoms are positioned at the edge of the MoS[sub 2] particles, in the same place as the Mo atoms. The CoMoS phase in all catalysts shows a well defined Co-Mo and a Mo-Co coordination. On alumina the CoMoS type II phase is present as a multilayer structure. The silica-supported CoMoS type II closely resembles its alumina-supported counterpart. However, the Mo-S coordination number, the structural ordering and degree of stacking of the carbon-supported type II CoMoS phase is much more similar to the type I CoMoS phase supported on alumina. This contradicts the common opinion that the CoMoS type II phase is fully sulfided and not chemically bonded to the support. Two different types of Co-sites can be distinguished in the suite of catalysts studied in this paper. A Co-site with an approximately fivefold Co-S coordination and possibly a single Co-Mo coordination is predominant in the least activemore » alumina-supported CoMoS type I and CoMoS type II (with Co/Mo = 0.39 at/at) samples. The other Co-site has a sixfold Co-S coordination with possibly a twofold Co-Mo coordination and has the highest activity for HDS. The latter site constitutes a large part of the Co-sites in silica-supported CoMoS phase II and alumina-supported CoMoS type (II) (with Co/Mo = 0.32) and is exclusively present in the carbon-supported CoMoS phase II. 46 refs., 9 figs., 3 tabs.« less

Authors:
; ; ;  [1];  [2];  [3]
  1. Eindhoven Univ. of Technology (Netherlands)
  2. Koninklijke/Shell Laboratorium Amsterdam (Netherlands)
  3. Delft Univ. of Technology, Mekelweg (Netherlands)
Publication Date:
OSTI Identifier:
7036838
Resource Type:
Journal Article
Journal Name:
Journal of Catalysis; (United States)
Additional Journal Information:
Journal Volume: 146:2; Journal ID: ISSN 0021-9517
Country of Publication:
United States
Language:
English
Subject:
37 INORGANIC, ORGANIC, PHYSICAL AND ANALYTICAL CHEMISTRY; COBALT SULFIDES; STRUCTURAL CHEMICAL ANALYSIS; MOLYBDENUM SULFIDES; ABSORPTION SPECTROSCOPY; ALUMINIUM OXIDES; CATALYST SUPPORTS; CATALYSTS; PHOTOELECTRON SPECTROSCOPY; X-RAY SPECTROSCOPY; ALUMINIUM COMPOUNDS; CHALCOGENIDES; COBALT COMPOUNDS; ELECTRON SPECTROSCOPY; MOLYBDENUM COMPOUNDS; OXIDES; OXYGEN COMPOUNDS; REFRACTORY METAL COMPOUNDS; SPECTROSCOPY; SULFIDES; SULFUR COMPOUNDS; TRANSITION ELEMENT COMPOUNDS; 400201* - Chemical & Physicochemical Properties

Citation Formats

Bouwens, S M.A.M., Zon, F B.M. van, Veen, J A.R. van, Koningsberger, D C, Dijk, M.P. van, and Kraan, A.M. van der. On the structural differences between alumina-supported CoMoS type I and alumina-, silica, and carbon-supported CoMoS type II phases studied by XAFS, MES, and XPS. United States: N. p., 1994. Web. doi:10.1006/jcat.1994.1076.
Bouwens, S M.A.M., Zon, F B.M. van, Veen, J A.R. van, Koningsberger, D C, Dijk, M.P. van, & Kraan, A.M. van der. On the structural differences between alumina-supported CoMoS type I and alumina-, silica, and carbon-supported CoMoS type II phases studied by XAFS, MES, and XPS. United States. doi:10.1006/jcat.1994.1076.
Bouwens, S M.A.M., Zon, F B.M. van, Veen, J A.R. van, Koningsberger, D C, Dijk, M.P. van, and Kraan, A.M. van der. Fri . "On the structural differences between alumina-supported CoMoS type I and alumina-, silica, and carbon-supported CoMoS type II phases studied by XAFS, MES, and XPS". United States. doi:10.1006/jcat.1994.1076.
@article{osti_7036838,
title = {On the structural differences between alumina-supported CoMoS type I and alumina-, silica, and carbon-supported CoMoS type II phases studied by XAFS, MES, and XPS},
author = {Bouwens, S M.A.M. and Zon, F B.M. van and Veen, J A.R. van and Koningsberger, D C and Dijk, M.P. van and Kraan, A.M. van der},
abstractNote = {In this study the local structure of the Mo and Co promoter atoms in CoMoS type I and II on alumina, and CoMoS type II on various supports is compared using in situ XAFS spectroscopy as the main technique with XPS and MES in a supporting role. In the CoMoS phase the Co atoms are positioned at the edge of the MoS[sub 2] particles, in the same place as the Mo atoms. The CoMoS phase in all catalysts shows a well defined Co-Mo and a Mo-Co coordination. On alumina the CoMoS type II phase is present as a multilayer structure. The silica-supported CoMoS type II closely resembles its alumina-supported counterpart. However, the Mo-S coordination number, the structural ordering and degree of stacking of the carbon-supported type II CoMoS phase is much more similar to the type I CoMoS phase supported on alumina. This contradicts the common opinion that the CoMoS type II phase is fully sulfided and not chemically bonded to the support. Two different types of Co-sites can be distinguished in the suite of catalysts studied in this paper. A Co-site with an approximately fivefold Co-S coordination and possibly a single Co-Mo coordination is predominant in the least active alumina-supported CoMoS type I and CoMoS type II (with Co/Mo = 0.39 at/at) samples. The other Co-site has a sixfold Co-S coordination with possibly a twofold Co-Mo coordination and has the highest activity for HDS. The latter site constitutes a large part of the Co-sites in silica-supported CoMoS phase II and alumina-supported CoMoS type (II) (with Co/Mo = 0.32) and is exclusively present in the carbon-supported CoMoS phase II. 46 refs., 9 figs., 3 tabs.},
doi = {10.1006/jcat.1994.1076},
journal = {Journal of Catalysis; (United States)},
issn = {0021-9517},
number = ,
volume = 146:2,
place = {United States},
year = {1994},
month = {4}
}