Elucidation of sulfidation state and hydrodesulfurization mechanism on TiO2 catalysts using S-35 radioisotope tracer methods

Citation
Dh. Wang et al., Elucidation of sulfidation state and hydrodesulfurization mechanism on TiO2 catalysts using S-35 radioisotope tracer methods, J CATALYSIS, 203(2), 2001, pp. 322-328
Citations number
38
Language
INGLESE
art.tipo
Article
Categorie Soggetti
Physical Chemistry/Chemical Physics","Chemical Engineering
Journal title
JOURNAL OF CATALYSIS
ISSN journal
0021-9517 → ACNP
Volume
203
Issue
2
Year of publication
2001
Pages
322 - 328
Database
ISI
SICI code
0021-9517(20011025)203:2<322:EOSSAH>2.0.ZU;2-C
Abstract
The hydrodesulfurization (HDS) activities of sulfided TiO2 with various sur face areas were characterized under the typical HDS reaction conditions. Th e results showed that HDS activities increased linearly with increasing sur face area of TiO2, suggesting that the surface sulfide TiS2 is the active p hase of the HDS reaction on sulfided TiO2 catalyst. The sulfidation states of TiO2 with various surface areas were investigated using a S-35 radioisot ope pulse tracer method. The results showed that the Ti atoms on the surfac e of TiO2 could be completely sulfided to TiS2 at 400 degreesC, whereas the sulfidation of Ti atoms in the bulk of TiO2 would occur slowly at 500 degr eesC. When the sulfided TiO2 was reduced in H-2 at 400 degreesC, TiS2 was r educed to the sulfidation state TiS1.5, leading to the formation of Ti3+ io ns and sulfur anion vacancies. Moreover, HDS reaction mechanisms on sulfide d TiO2 catalysts under the reaction conditions were elucidated by a 35S rad ioisotope tracer method using S-35-labeled dibenzothiophene (DBT). The resu lts showed that less labile sulfur was detected on the sulfided TiO2 cataly sts, suggesting that the HDS mechanism on TiO2 catalysts was very different from that on Mo-based catalysts. (C) 2001 Academic Press.