Selective Hydrogenation of Furfural to 2-Methyltetrahydrofuran over Bimetallic Ru–Ni Nanoparticles Supported on Nanocrystalline CeO ₂

Nanocrystalline ceria (CeO2) with engineered surface defects provides a versatile platform for constructing catalytically active metal-oxide interfaces. Herein, we report defect-rich nanocrystalline CeO2-supported bimetallic Ru–Ni nanoparticles, in which electronically coupled interfacial sites govern selective biomass upgrading. Structural and spectroscopic analyses (XRD, TEM, XPS, EPR, Raman, H2-TPR/TPD, and NH3-TPD) reveal strong metal–support interactions, abundant oxygen vacancies, and nanoscale Ru–Ni proximity, which promote interfacial electronic coupling without alloy formation. The optimized 3Ru-5Ni/CeO2 catalyst achieves complete conversion of furfural (FAL) with 92% selectivity toward 2-methyltetrahydrofuran (2-MTHF) at 200 °C and 0.5 MPa H2 in 2 h. Reaction optimization, substrate transformation studies, kinetic studies, and pyridine poisoning experiments establish a sequential pathway involving FAL hydrogenation to furfuryl alcohol (FOL), its hydrodeoxygenation to 2-methylfuran (2-MF), and final ring hydrogenation to 2-MTHF. The enhanced performance originates from cooperative nanoscale interactions in which Ru facilitates H2 dissociation, Ni promotes C–O bond activation, and vacancy-rich CeO2 enables hydrogen spillover and intermediate stabilization. These findings demonstrate how defect engineering and bimetallic interface design in nanostructured oxide supports can precisely steer reaction pathways for sustainable upgrading of biomass-derived furans.