Effect of silver doping on the phase transformation and grain growth of sol-gel titania powder

Pure and Ag doped TiO2 powders were prepared by the sol-gel process. The effect of Ag doping on TiO2 anatase to rutile phase transformation was investigated by means of XRD, TEM, SEM, DSC-TG, and surface morphological characterization. It is found that the Ag doping promotes the phase transformation but has a depression effect on the anatase grain growth. The mechanism is proposed. With a suitable amount (ca. 2-6 mol%), the Ag dopant reduces anatasegrain size and increases the specific surface area of TiO2 powder, which exhibits a great potential in improving the TiO2 photocatalytic activity. (C) 2002 Elsevier Science Ltd. All rights reserved.