NiCo and NiCo Decorated with Ru Nanoparticles for Magnetically Induced Hydroprocessing of Lignin Models

A series of bimetallic Ni10-xCox (x: 2, 3, 4, 5) nanoparticles have been prepared using the organometallic approach from Ni[(PrNC)-Pr-i(CH3)(NPr)-Pr-i](2) and Co[N(SiMe3)(2)](2)(thf) precursors. Structural characterization by high-resolution transmission electron microscopy (HR-TEM), X-ray absorption spectroscopy (XAS), and X-ray diffraction (XRD) revealed a bimetallic structure with a face-centered cubic (fcc) Ni-rich core and ultrasmall (<= 2 nm) hcp Co nanoparticles decorating it. Magnetic and magnetic hyperthermia properties were measured by vibrating sample magnetometry (VSM) and calorimetry, respectively. Moreover, the Ni7Co3 composition was shown to be a stable heterogeneous catalyst for diphenyl ether (DPE) hydrogenation under magnetic induction. Remarkably, the Ni7Co3 system before and after its decoration with a small amount of Ru (1 wt %) was transposed to the low-pressure hydrogenation of lignin-linkage models and lignin-oil molecules. The results showed that the system had moderate activity in cleaving different ether C-O bonds and was effective in upgrading lignin oils through hydrodeoxygenation (HDO), with a significant preference to produce cyclohexanols. This study represents a significant step toward applications of magnetic-induced catalysis in the field of biomass valorization.