A highly hydroxylated barium titanate (BaTiO 3 ) nanopowder has been prepared by oxidizing the BaTiO 3 with an aqueous solution of hydrogen peroxide (H 2 O 2 ). The concentration of the hydroxyl group (–OH) derived on the BaTiO 3 surface by H 2 O 2 -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 BaTiO 3 to 25.0% on the H 2 O 2 -treated BaTiO 3 . The characterization results of XPS analysis and zeta-potentials show that the surface –OH is primary on the barium (Ba) site of the BaTiO 3 , and this Ba-attached –OH is Bronsted-basic. Since the H 2 O 2 -treated BaTiO 3 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 H 2 O 2 -treated BaTiO 3 than on the as-received BaTiO 3 .
Institute of Materials Science and Engineering, and Department of Materials & Mineral Resources Engineering, National Taipei University of Technology, Box 2761, 1, Sec. 3, Zhongxiao E. Rd, Taipei 10608, Taiwan
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