Effects of compositional impurity on surface chemistry of TiO2 nanopowder and its chemical interactions with dispersants

► Commercial TiO2 nanopowder is covered with a thick layer of SiO2 that is 2-3 nm. ► Surface-treatment by HCl(aq) efficiently thins the SiO2 layer and decreases the acidity of TiO2. ► Both alkaline and acidic surfactants prefer to adsorb on the HCl-treated TiO2.