Total hydrogenation of furfural under mild conditions over a durable Ni/TiO₂−SiO₂ catalyst with amorphous TiO₂ species

One-step total hydrogenation of furfural (FAL) toward tetrahydrofurfuryl alcohol in continuous flow using cheap transition metals still remains a great challenge. We herein reported the total hydrogenation of FAL over Ni (∼5 nm) nanoparticles loaded on TiO₂−SiO₂ composites with long-term stability. The TiO₂−SiO₂ composites comprise amorphous TiO_x which was grafted on the silica aerogel by acetyl acetone-aided controlled hydrolysis of tetrabutyl titanate. The catalysts were characterized by several techniques including Brunauer−Emmett−Teller, X-ray diffraction, transmission electron microscopy, H₂-temperature-programmed reduction, and H₂-temperature-programmed desorption. The hydrogenation performances were systematically explored in terms of TiO₂ content, Ni loading, liquid hour space velocity, and so forth. Ni nanoparticles in contact with amorphous TiO_x showed strengthened interaction with the C=O bond of FAL as well as enhanced hydrogen dissociation and desorption ability, hence benefiting the overall hydrogenation process.