Efficient hydroxylation of BaTiO3 nanoparticles by using hydrogen peroxide

A highly hydroxylated barium titanate (BaTiO3) nanopowder has been prepared by oxidizing the BaTiO3 with an aqueous solution of hydrogen peroxide (H2O2). The concentration of the hydroxyl group (–OH) derived on the BaTiO3 surface by H2O2-treatment is determined by the quantitative X-ray photon spectroscopy (XPS) method, and the calculation result shows that the OH fraction on the particle surface increases significantly from 9.2% on the as-received BaTiO3 to 25.0% on the H2O2-treated BaTiO3. The characterization results of XPS analysis and zeta-potentials show that the surface –OH is primary on the barium (Ba) site of the BaTiO3, and this Ba-attached –OH is Bronsted-basic. Since the H2O2-treated BaTiO3 has significantly increased Bronsted-basic –OH on its surface, higher adsorption selectivity to the surface modification agent with carrying acidic functional group, such as benzoic acid, rather than the alkaline group, such as benzylamine, is observed. Moreover, the benzoic acid shows much more adsorption on the H2O2-treated BaTiO3 than on the as-received BaTiO3.