Issue 6, 2016

Effects of MoO3 crystalline structure of MoO3–SnO2 catalysts on selective oxidation of glycol dimethyl ether to 1,2-propandiol

Abstract

To improve the selectivity of 1,2-propandiol (PDO) by modifying the structure and morphology of the MoO3/SnO2 catalyst, orthorhombic (α), monoclinic (β) and hexagonal (h) MoO3 crystalline phases were prepared to investigate the rational design requirements of the MoO3–SnO2 structure that are beneficial for the reaction of glycol dimethyl ether (DMET) to PDO. With an increase in the reaction temperature, the highest PDO selectivity of the oxidation reaction of glycol dimethyl ether to 1,2-propandiol was always obtained over the h-MoO3–SnO2 catalyst and the lowest PDO selectivity was always obtained over the β-MoO3–SnO2 catalyst. The MoO3 bulk structure, the interaction between SnO2 and MoO3 and the surface properties of these three catalysts could account for this distinctive difference. Hexagonal MoO3 is dispersed more homogeneously over the h-MoO3–SnO2 catalyst due to the hexagonal crystalline tunnel structure existing in the h-MoO3–SnO2 catalyst, and the weak interaction between MoO3 and SnO2; besides, the more hydrated surface of the h-MoO3–SnO2 catalyst can lead to more Brønsted acid sites being present on the catalyst surface and favor the dissociation of the C–O bond in DMET and association of the C–C bond to form PDO with the assistance of the redox and basic sites, which can explain why the highest PDO was obtained over the h-MoO3–SnO2 catalyst. The lattice strain and oxygen vacancies in the β-MoO3–SnO2 catalyst, induced by the substitution of Sn4+ ions with the smaller sized Mo6+ ions, enhance the oxidation ability of the β-MoO3–SnO2 catalyst, and consequently more CH3O· can be formed and transformed to formaldehyde (FA) and methyl formate (MF), which can explain why the total selectivity of FA and MF was highest while the selectivity of PDO was lowest over the β-MoO3–SnO2 catalyst at the same time. These findings are pretty significant for further investigation of the rational design of the MoO3–SnO2 catalyst structure, applied to the conversion of DMET to PDO.

Graphical abstract: Effects of MoO3 crystalline structure of MoO3–SnO2 catalysts on selective oxidation of glycol dimethyl ether to 1,2-propandiol

Supplementary files

Article information

Article type
Paper
Submitted
16 Jun 2015
Accepted
13 Oct 2015
First published
15 Oct 2015

Catal. Sci. Technol., 2016,6, 1842-1849

Author version available

Effects of MoO3 crystalline structure of MoO3–SnO2 catalysts on selective oxidation of glycol dimethyl ether to 1,2-propandiol

Z. Zhang, Q. Zhang, L. Jia, W. Wang, H. Xiao, Y. Han, N. Tsubaki and Y. Tan, Catal. Sci. Technol., 2016, 6, 1842 DOI: 10.1039/C5CY00894H

To request permission to reproduce material from this article, please go to the Copyright Clearance Center request page.

If you are an author contributing to an RSC publication, you do not need to request permission provided correct acknowledgement is given.

If you are the author of this article, you do not need to request permission to reproduce figures and diagrams provided correct acknowledgement is given. If you want to reproduce the whole article in a third-party publication (excluding your thesis/dissertation for which permission is not required) please go to the Copyright Clearance Center request page.

Read more about how to correctly acknowledge RSC content.

Social activity

Spotlight

Advertisements