Structure of the active sites on H3PO4/ZrO2 catalysts for dimethyl carbonate synthesis from methanol and carbon dioxide

Citation
Y. Ikeda et al., Structure of the active sites on H3PO4/ZrO2 catalysts for dimethyl carbonate synthesis from methanol and carbon dioxide, J PHYS CH B, 105(43), 2001, pp. 10653-10658
Citations number
15
Language
INGLESE
art.tipo
Article
Categorie Soggetti
Physical Chemistry/Chemical Physics
Journal title
JOURNAL OF PHYSICAL CHEMISTRY B
ISSN journal
1520-6106 → ACNP
Volume
105
Issue
43
Year of publication
2001
Pages
10653 - 10658
Database
ISI
SICI code
1520-6106(20011101)105:43<10653:SOTASO>2.0.ZU;2-S
Abstract
The catalytic properties of H3PO4/ZrO2 catalysts for dimethyl carbonate (DM C) synthesis from CH3OH and CO2 were investigated. The modification of ZrO2 with H3PO4 promoted the activity for selective DMC formation. The characte rization of H3PO4/ZrO2 catalysts was performed by means of BET, XRD, (31)p NIAS NMR, LRS, DRIFT, and NH3-TPD. From the characterization results, it wa s determined that ZrO2 had Lewis acid sites and did not have Bronsted acid sites. The presence of Bronsted acid sites as well as Lewis acid sites was observed on H3PO4/ZrO2 (P/Zr = 0.05). The acidity of the Bronsted sites is weak, and the site's structure is a bridged OH. Furthermore, this Bronsted site is formed by the interaction between tetragonal Zr and P. In the react ion scheme of DMC formation, the Bronsted acid site can contribute to CH3OH activation and to the enhancement of the catalytic activity.