Fabrication of Mesoporous NiAl2O4 Nanorods and Their Catalytic Properties for Toluene Hydrocracking

Abstract

Mesoporous single-crystalline NiAl2O4 nanorods were successfully synthesized by a one-step hydrothermal method using a pore-forming agent (NH4HCO3). A series of controlled experiments were also carried out to better understand the formation mechanism of NiAl2O4 nanorods. The experimental results indicate that the reaction time, reactant concentration and the amount of NH4HCO3 play an important role in determining the morphology. The morphology, structure and composition of the nanorods were investigated using transmission electron microscopy, high resolution transmission electron microscopy, scanning electron microscopy and X-ray diffraction. The specific surface area and pore-size distribution of the obtained product was determined by nitrogen adsorption-desorption measurements. NiAl2O4 nanorods have a high Brunauer-Emmett-Teller surface area and good porosity properties. The catalytic performance of the NiAl2O4 nanorods during toluene hydrocracking was investigated using a fixed bed reactor. After the toluene catalytic reactions over 400 min at a water stream/carbon molar ratio (H2O/C) of 1.0 with a reaction temperature of 700 °C the average conversion efficiency of toluene was about 86.5%. Compared to the NiAl2O4 nanoparticles prepared by alkaline precipitation, the mesoporous NiAl2O4 nanorods exhibited higher catalytic activity and stability during toluene hydrocracking. A possible formation mechanism for the mesoporous NiAl2O4 nanorods is proposed and discussed. © Editorial office of Acta Physico-Chimica Sinica.