Acidic and catalytic properties of dealuminated zeolite Y treated with zirconyl nitrate solution

Abstract

Structure, the constitution of a surface hydroxyl layer, and the acid properties and catalytic activity in n-hexane conversion were studied for dealuminated zeolites Y modified with zirconyl nitrate to have a zirconium loading of 0.2, 0.4, and 0.8 wt %. After dealumination with ammonium hexafluorosilicate solution and exchange for NH+4, the initial zeolites were calcined at 500–550°C and washed with an acid or alkali solution. The investigation techniques used were X-ray diffraction, thermal analysis, IR spectroscopy, X-ray photoelectron spectroscopy, and temperature-programmed ammonia desorption. It was found that the introduction of zirconium increased the relative amount of strong acid sites, thus increasing the yield of n-hexane cracking products.