Effect of heat treatment on structure of nickel-based catalysts

Abstract

Nickel-based catalyst is the general-purpose catalyst with a wide application and good performance. Widely used in fine chemicals, petrochemicals and other industries, it has received continuous attention from researchers. Taking silica gel (SiO2) and HZSM-5 molecular sieves as carriers, and Ni(NO3)2 · 6H2O and Cu(NO3)2 · 3H2O as precursors, in the work we prepared a series of NiO/SiO2, NiO/HZSM-5 and NiCu/HZSM-5 catalysts by impregnation method. Focused on the effects of heat treatment (baking) temperature and time on the structure of the catalysts, the structure of the catalysts was characterized by X-ray diffraction (XRD) spectroscopy. The results showed that in terms of carriers, HZSM-5 had stronger interaction with active metal particles than that SiO2 presented. It could better prevent the sintering agglomeration of catalytic particles during heat treatment, which is beneficial to preparing catalytic particles with smaller particle size. SiO2 exhibited better thermal stability for higher heat treatment temperatures and longer heat treatment time. At the same time, the heat treatment at the high temperature for a long time was liable to cause sintering growth of the active metal particles of the catalysts. The selection of suitable heat treatment process conditions was critical to obtaining the highly active nickel-based catalysts. The work briefly discussed the effect of heat treatment temperature and time on the structure of the catalysts, expecting to provide the useful reference for the preparation technology of supported nickel-based catalysts.