Highly Effective Sulfated Zirconia Nanocatalysts Grown out of Colloidal Silica at High Temperature

Authors:
Publisher website
Google Scholar
Abstract
A large surface‐to‐volume ratio is a prerequisite for highly effective catalysts. Making catalysts in the form of nanoparticles provides a good way to achieve the aim. However, agglomeration of nanoparticles during the preparation and utilization of nanocatalysts remains a formidable problem. Here, we present a novel approach in which nano units of catalysts are formed in the matrix of a colloidal carrier, with assistance of a cross‐linking agent, and then grow out of the carrier upon calcination at high temperature. This ensures that the catalysts not only do not agglomerate, but also have a low cost and high catalytic efficiency due to the large surface‐to‐volume ratio and the absence of carbon deposition. The technique is demonstrated by the successful preparation of a binary nanocatalyst that consists of a silica nanoparticle core and a sulfated zirconia (SZ) nanocrystal shell (JML‐1). The synthesis was achieved by converting sulfated zirconia (SZ) and silica solutions into a composite gel by means of sol–gel processing in the presence of triethoxysilane as the cross‐linking agent, followed by heating at 50 °C and calcining at 550 °C. Relative to other catalysts, such as pure SZ, non‐nanodispersed SZ over silica (SZ/SiO2), and zeolites Y, Beta, and ZSM‐5, JML‐1 exhibits superior catalytic activity in many reactions. For example, the activity of JML‐1 in the production of gasoline by alkylation of 1‐butene with isobutene remained at 95 % or higher after 20 h of reaction and was over 90 % after being regenerated five times. In sharp contrast, SZ and SZ/SiO2 give a high activity only for 2 h and the initial activity of zeolites Beta and ZSM‐5 are about 88 and 60 %, respectively. These findings demonstrate that non‐agglomerated nanoparticles anchored onto a carrier surface can be prepared and the technique provides a versatile route to new highly effective nanocatalyst systems.

This publication has 24 references indexed in Scilit: