The catalytic properties of H3PO4/ZrO2 catalysts for dimethyl carbonate (DMC) synthesis from CH3OH and CO2 were investigated. The modification of ZrO2 with H3PO4 promoted the activity for selective DMC formation. The characterization of H3PO4/ZrO2 catalysts was performed by means of BET, XRD, 31P MAS NMR, LRS, DRIFT, and NH3-TPD. From the characterization results, it was determined that ZrO2 had Lewis acid sites and did not have Brønsted acid sites. The presence of Brønsted acid sites as well as Lewis acid sites was observed on H3PO4/ZrO2 (P/Zr = 0.05). The acidity of the Brønsted sites is weak, and the site's structure is a bridged OH. Furthermore, this Brønsted site is formed by the interaction between tetragonal Zr and P. In the reaction scheme of DMC formation, the Brønsted acid site can contribute to CH3OH activation and to the enhancement of the catalytic activity.
ASJC Scopus subject areas
- Physical and Theoretical Chemistry
- Surfaces, Coatings and Films
- Materials Chemistry