Analytical TEM study on the dispersion of Au nanoparticles in Au/TiO2 catalyst prepared under various temperatures

Transmission electron microscopy (TEM) observations were made for Au/TiO2 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 TiO2. Many Au clusters with diameters of similar to1 nm were observed on the TiO2 surface when Au(OH)(3)/TiO2 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 TiO2 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 TiO2 particles that have the rutile structure. Copyright (C) 2001 John Wiley & Sons, Ltd.