Source: University of Tokyo
On February 7, 2025, the University of Tokyo announced that a research team from its Graduate School of Engineering and Tokyo Metropolitan University had successfully developed a solid catalyst capable of hydrogenolysis of epoxy resin composites. This catalyst can efficiently decompose epoxy resin under mild conditions and has been successfully applied to the recycling of carbon fiber-reinforced plastics (CFRP) and glass fiber-reinforced epoxy substrates. The research team hopes that this achievement can drive the development of recycling technology for epoxy resin composites.
To decompose fiber-reinforced plastics, it is necessary to decompose the epoxy resin in the bonded part. However, this usually requires temperatures above 500°C or strong acid or alkaline environments, and it is difficult to recover both fibers and resin monomers. Although hydrogenolysis methods using homogeneous catalysts for epoxy resin have been developed in recent years, catalyst recovery and reuse remain challenging.
The catalyst developed by the research team is a cerium oxide-supported nickel-palladium bimetallic catalyst (Ni-Pd/CeO2), prepared using nickel chloride and palladium chloride as metal precursors through a sodium hydroxide coprecipitation method. Analysis of the catalyst using high-angle annular dark-field scanning transmission electron microscopy (HAADF-STEM) and energy-dispersive X-ray spectroscopy (EDS) revealed that nickel and palladium are loaded as alloy nanoparticles at the same location on the surface of cerium oxide.
Using this catalyst in an N-methylpyrrolidone (NMP) solvent under conditions of 180°C and atmospheric pressure hydrogen, the decomposition reaction of acid anhydride or amine-cured epoxy resin proceeds smoothly, and the corresponding phenolic compounds are successfully recovered. In addition, the decomposition reaction is significantly accelerated by adding a catalytic amount of base.
The Ni-Pd/CeO2 catalyst system can also decompose CFRP and glass epoxy substrates and recover fibers and phenolic compounds through hydrogenolysis of epoxy resin. Analysis of the recovered fibers using scanning electron microscopy (SEM) confirmed complete decomposition of the epoxy resin and a clean fiber surface. Furthermore, the catalyst exhibits excellent stability and can still efficiently decompose CFRP even after being reused six times.
The research results were published online in the British scientific journal Nature Communications on February 6.
