Facile synthesis of magnetic recyclable Fe₃O₄@PDA@MoS₂ nanocomposites for effectively hydrocracking of residue

Magnetic nanocomposites provide manifold perspectives for sustainable development. However, the cumbersome operation process and energy consumption after treatment limit its application in the practical industry. Herein, we present a simple and universal strategy to synthesize Fe₃O₄@PDA@shell nanoparticles via in-situ homogeneous hydrolysis reaction growth different nanomaterials on the PDA modified Fe₃O₄ nanospheres, which can avoid multistep repetitive washing, redispersing, and drying. As an example, we introduced the synthesis process of Fe₃O₄@PDA@MoS₂ catalyst used for heavy oil hydrocracking in detail. The synthesis processes were significantly simplified and the dispersity and stability of the nanosized MoS₂ were improved due to the copious functional groups and strong adhesion properties of polydopamine. The as-prepared Fe₃O₄@PDA@MoS₂ nanoparticle catalysts showed high activity and excellent stability. The viscosity of residue was decreased by 99.8% and the recovery of the catalyst reached 90% under harsh conditions (405 ℃ at 13 MPa H₂). We also demonstrate the versatility of this strategy for other shell materials, such as WS₂, VS₂, Pd, and Rh components, which is promising for designing multifunctional core−shell−shell materials for various applications.