Selective Enhancement of Photo-Piezocatalytic Performance in BaTiO3 Via heterovalent Ion Doping

This study proposes a strategy based on heterovalent ion doping that gives rise to a synergistic piezo-phototronic effect with significantly improved catalytic activity and leads to selective catalytic enhancement for specific pollutants. Owing to the enhanced light absorption, hydrogen evolution rates are as high as 3704 and 3178 mu molg(-1) h(-1) in 0.01Li-doped BaTiO3 and 0.02La-doped BaTiO3 nanosheets, respectively, under simultaneous irradiation by ultrasound and light, a factor of 4.6 and 3.9 times higher than for pure BaTiO3. The performance also far exceeds that of single piezocatalysis, photocatalysis, or the sum of the two for Li/La-doped BaTiO3 nanosheets due to the effects of the piezoelectric field in promoting photo-induced separation of electron-hole pairs. Further, by carefully selecting donor or acceptor doping, a significant enhancement in catalyst to specific pollutants is obtained by controlling the band structure. Compared to pure BaTiO3, 0.01Li-doped BaTiO3 possesses higher catalytic activity for anionic dyes such as Methyl blue and Malachite Green, reaching 0.067 and 1.379 min(-1), respectively, while 0.02La-doped BaTiO3 exhibits better catalytic performance for cationic dyes such as Rhodamine B and Methyl Orange, with degradation rates up to 0.274 and 0.029 min(-1), respectively. This study offers a path to the design of efficient piezocatalysts for specific applications.