Highly stable mesoporous Ni-phyllosilicate particle under high temperature hydrothermal and base conditions towards industrial catalytic applications

Abstract

Two mesoporous nickel phyllosilicate (Ni-PS) samples with Ni/Si ratios of 0.3 and 1 were used to compare high-temperature hydrothermal stability. The Ni-PS structures have well-developed porosity and pore size distributions mainly ranging from 2 to 20 nm. To assess their hydrothermal resistance as a reusable heterogeneous catalyst in high-temperature reactions, the samples were exposed to 800 °C for 7 days using steam-supplied muffle furnaces. Three types of mesoporous silica samples (i.e. MCM-41, SBA-15, and mesoporous benzene-silica) and two zeolites (i.e. ZSM-5 and zeolite-Y) were compared under the same conditions. The hydrothermal resistance was primarily confirmed based on changes in pore size distribution and surface area through nitrogen-sorption isotherm analysis. The crystal structure and the binding energy of each sample were investigated by X-ray diffraction and X-ray photoelectron spectroscopy measurements. The Ni-PS structures displayed excellent stability (i.e. BET surface area retained over 77 % and 65 % after 1-d and 7-d treatment, respectively.) compared with other mesoporous samples, and even higher stability than zeolite Y. In addition, structural stability at pH = 10 is much higher than that of ZSM-5. This suggests that it could be used for various catalytic chemical reactions including hydrogenation and cracking processes because NiO and Ni nanoparticles are uniformly distributed on the surface, maintaining their particle shape even after a reduction process.