Preparation of Ni, CoO-supported halloysite nanotube catalyst and its application in the hydrogenation of furfural to furfuryl alcohol

摘要

In this study, halloysite (Hal) nanotubes were designed as a carrier and stabilizer as well as a nanostructured matrix. A series of Ni, CoO-Hal catalysts were then synthesized through a deposition method. The catalysts were characterized by X-ray diffraction, X-ray photoelectron spectroscopy (XPS), Fourier-transform infrared spectroscopy, scanning electron microscopy, and transmission electron microscopy. The catalytic properties of the catalyst were evaluated using the hydrogenation of furfural to furfuryl alcohol. The average pore size of activated Hal ranged from 20 nm to 32 nm, and the specific surface areas of Hal increased up to 125.55 m(2)/g. The Ni or CoO particles were successfully loaded on the external surface of Hal nanotubes with diameters of approximately 10 nm. The XPS data confirmed zero-valent character for metal Ni at 852.6 eV and the oxide form for metal Co with type of CoO and Co3O4; meanwhile, a small amount of nickel protoxide was observed due to the weak oxidation on the surface of metal Ni. The evaluation of catalytic activities showed that the Ni-Hal catalyst presented favorable selectivity to furfural alcohol (approximately at 99.0%) and good furfural conversion. The successive catalytic cycles indicated that the furfural conversion and selectivity to furfural alcohol of the prepared catalyst maintained good stability (approximately at 96% and 65%, respectively).