Piezo-photocatalytic properties of BaTiO 3 /CeO 2 nanoparticles with heterogeneous structure synthesized by a gel-assisted hydrothermal method.

BaTiO 3 /CeO 2 nanoparticles with heterogeneous structure were successfully synthesized via a gel-assisted hydrothermal method. The molar ratio of Ti/Ce was set as 1 : 0, 0.925 : 0.075, 0.9 : 0.1; 0.875 : 0.125, and 0.85 : 0.15 in the dried gels. Affected by the values of Ti/Ce, the particle sizes of hydrothermal products decreased obviously, and the surface of nanoparticles became rough and even had small protrusions. XRD, SEM, HRTEM, XPS, DRS, ESR, and PFM were used to characterize the nanoparticle textures. We speculated that the main body and surface of nanoparticles were BaTiO 3 and CeO 2 protrusions, respectively. The catalytic performance of BaTiO 3 /CeO 2 nanoparticles was characterized by their abilities to degrade RhB in water under different external conditions (light irradiation, ultrasonic oscillation, or both). In all test groups, BaTiO 3 /CeO 2 nanoparticles with a Ti/Ce molar ratio of 0.875 : 0.125 in the initial dried gel exhibited the strongest catalytic ability when light irradiation and ultrasonication were applied simultaneously owing to the appropriate amount of Ce 3+ and oxygen vacancies.