Measurement of acid–base properties on metal oxide surfaces in aqueous solution

Abstract

A potentiometric acid–base titration method was used to investigate the surface properties of metal oxides in aqueous solution. The metal oxides used were SiO₂, γ-Al₂O₃, ZrO₂, TiO₂, SiO₂–Al₂O₃, SiO₂–ZrO₂ and TiO₂–ZrO₂. The amounts of protonated hydroxyl group [graphic omitted] M—OH⁺₂ and of ionized hydroxyl group [graphic omitted] M—O^– present were studied as a function of solution pH. The results are consistent with those obtained by a n-butylamine titration method or a gas adsorption method.