One-pot direct synthesis route to self-assembled highly ordered Zn-decorated mesoporous aluminium oxide toward efficient and sustainable metathesis heterogeneous catalyst design

Abstract

Hexagonally well-organized ZnCl₂-OMA materials have been successfully synthesized by a one-pot approach using a sol–gel method at ambient temperature and pressure. These materials were prepared through simultaneous self-assembly process with F127 as directing agent combined with in situ impregnation of ZnCl₂. The new approach was found to be compatible with various common aluminium precursors and carboxylic acids used as self-assembly interfacial protectors. The obtained ZnCl₂-OMA materials were fully characterized using XRD, N₂ adsorption–desorption, TEM, SEM, EDX, XPS and ¹H and ²⁷Al MAS-NMR techniques. These materials were compared with the zinc chloride-doped organized mesoporous alumina (ZnCl₂-OMA) supports prepared through a conventional two steps process that includes OMA synthesis and then post-synthesis incorporation of ZnCl₂. Thus, the one-pot synthesized materials were found to exhibit improved properties compared to the conventional ones, particularly larger BET surface area. The synthesized ZnCl₂-OMA materials were then used as catalytic supports for methyltrioxorhenium (MTO), showing enhanced catalytic performance for methyl oleate self-metathesis, demonstrating better activity and selectivity towards desired metathesis products. These features are highly beneficial for large-scale materials synthesis through fast, simple, easy and low-cost introduction of functionalities on mesoporous materials surface without multi-step procedures.