Analytical TEM study on the dispersion of Au nanoparticles in Au/TiO 2 catalyst prepared under various temperatures

Abstract

Transmission electron microscopy (TEM) observations were made for Au/TiO 2 catalysts prepared by calcination in air at different temperatures from room temperature to 873 K in order to study the growth process of Au particles over the surface of TiO 2 . Many Au clusters with diameters of ∼1 nm were observed on the TiO 2 surface when Au(OH) 3 /TiO 2 precursor prepared by the deposition precipitation method was calcined at temperatures below 473 K. They grew to form larger particles being trapped at the interface between TiO 2 particles at temperatures above 573 K. The growth of Au particles became markedly rapid above 673 K. The growth process of Au particles during calcination was discussed based on the size distribution of Au particles and the Arrhenius plots of the mean diameter of Au particles against calcination temperature. Both TEM and electron energy‐loss spectroscopy measurements based on a scanning transmission electron microscope revealed that the Au clusters were preferentially deposited with high density on specific TiO 2 particles that have the rutile structure. Copyright © 2001 John Wiley & Sons, Ltd.