4,6-Dimethyldibenzothiophene Hydrodesulfurization on Nickel-Modified USY-Supported NiMoS Catalysts: Effects of Modification Method

Abstract

The effects of the method of modifying USY zeolite with nickel on the hydrodesulfurization (HDS) of 4,6-dimethyldibenzothiophene (4,6-DMDBT) have been investigated. USY zeolites were modified with a small amount of Ni by three different methods, namely, the in situ synthesis method, the ion-exchange method, and the impregnation method, and the resulting Ni-modified USY zeolites were used as supports for NiMo sulfide catalysts. We found that the Ni modification method affects the textural properties, the acidity of the Ni-modified USY zeolites, the Ni–Mo–S active-phase morphology, the dispersion of the active metals, the structure of the Ni–Mo–S active phase, the sulfidation degree of the active metals, the 4,6-DMDBT HDS reaction rate constant, the turnover frequency, and the selectivity of the 4,6-DMDBT HDS pathways. Although the impregnation modification method was found to promote the dispersion of active metals most strongly and the ion-exchange modification method was found to enhance the sulfidation ...