One-pot synthesized core/shell structured zeolite@copper catalysts for selective hydrogenation of ethylene carbonate to methanol and ethylene glycol

Abstract

Copper-based catalysts, with highly dispersed and stabilized Cu nanoparticles, intensified mass transfer and a well-balanced Cu⁰/Cu⁺ ratio at low Cu loadings, are highly desirable for the selective hydrogenation of ethylene carbonate to ethylene glycol and methanol, an efficient indirect route of CO₂ utilization. A hierarchically core/shell-structured Silicalite-1@Cu composite was developed via a base-assisted chemoselective host–guest interaction between the silicon species of MFI-type Silicalite-1 and external Cu salt source. In situ generated mesoporosity and strong Cu–silicate interaction made the uniform Cu NPs firmly immobilized and highly dispersed outside the core S-1 crystals. The S-1@Cu hybrid possessed the co-existing Cu⁰/Cu⁺ active species with a suitable ratio, and served as a highly active, selective and robust catalyst for selective ethylene carbonate hydrogenation, providing a lifetime >350 h together with >99% ethylene carbonate conversion, >99% ethylene glycol yield, and more importantly 93% methanol yield at a relatively low Cu loading of 21.4 wt%.