Effect of Ga and in doping on acid centers and oxygen chemisorption on the surface of nanocrystalline ZnO

Abstract

Nanocrystalline gallium- and indium-doped zinc oxide samples have been prepared through coprecipitation from aqueous solutions. Acid centers on the surface of the materials have been investigated using temperature-programmed desorption and IR spectroscopy. The results demonstrate that, with increasing dopant concentration, the density of OH groups on the surface of ZnO〈Ga〉 and ZnO〈In〉 increases and the contribution of cation centers to surface acidity decreases. The interaction of the material with oxygen has been studied using in situ electrical conductivity measurements. Doping of zinc oxide with gallium or indium has been shown to increase the percentage of molecular chemisorbed oxygen species on the surface of the material.