Enhanced catalytic activity of Molar-like BaTiO3 by oxygen vacancies

Oxygen vacancies are found to have significant effects on the piezo-photocatalytic performance. For this reason, Molar-like and Bamboo-like BaTiO3 with the same tetragonal phase are synthesized by a two-step hydrothermal method. Molar-like BaTiO3 exhibits a superior piezo-photocatalytic performance by degrading the organic dye indigo carmine (IC), whose kinetic constant of 0.099 min−1 is 1.80 times higher than that of Bamboo-like BaTiO3. The same conclusion is drawn while the differences in specific surface areas are eliminated. There are more oxygen vacancies in Molar-like BaTiO3 compared to Bamboo-like BaTiO3, as shown in XPS results. The oxygen vacancies are favorable for light adsorption and O2 activation, thus an excellent photocatalytic performance is achieved. XRD refinements show that Molar-like BaTiO3 has a slightly higher content of piezoelectric tetragonal phase and stronger lattice distortion than Bamboo-like BaTiO3. However, the piezoelectric polarization of Molar-like BaTiO3 is weakened and the number of effective carriers is reduced due to more oxygen vacancies. The presented work provides a profound reference for the structural design of catalysts.