Development of stable water-resistant Cu-based catalyst for methanol synthesis

Abstract

Improving the stability of Cu-based catalysts, especially in the presence of water, has always been a great challenge. The hydrophobization strategy and effects on the catalyst surface property and catalytic performance deserve rigorous investigations. Herein, the hydrophobic modified silica was introduced as a support for CuZn catalyst to hinder the adsorption of water on active sites of Cu-based catalysts, thereby improving its stability. And silane agents (methyltrimethoxysilane, ethyltrimethoxysilane, propyltrimethoxysilane) were selected to modify the SiO2 surface by a reaction between the silane agent and the hydroxyl groups on the silica surface. After modification, the catalysts exhibited the better stability for methanol synthesis in the presence of water. FT-IR, BET, H2-TPR, XRD, TEM, XPS characterization were employed to determine the surface physical properties, reduction properties, crystal structure and particle size of the catalysts before and after the reaction. The results showed that water can simultaneously cause the oxidation and growth of Cu species resulting in the deactivation of Cu-based catalyst. However, the introduction of hydrophobic groups reduced the contact time between water and the active center, which prevented the growth and oxidation of Cu species, thus improving the catalyst stability.