Enhanced Piezocatalytic Performance of (Ba,Sr)TiO₃ Nanowires to Degrade Organic Pollutants

The discovery of piezocatalysts opens up a new route to wastewater decontamination. The piezoelectricity of barium titanate nanocrystals induced by ultrasonic vibration was found effective to degrade organic pollutants. In the present work, the products of (Ba,Sr)TiO3 (BST) nanocrystals with different morphologies including nanowires (NWs), nanoparticles (NPs) and their composite were synthesized by a template hydrothermal method. And, the piezocatalytic behavior of them was thoroughly investigated with respect to a possible influence of lowered phase transition temperature on the piezocatalytic behavior. It was found that the elongated BST nanowires were more effective in degrading dye pollutants in comparison with the pure BaTiO3 nanowires and BST nanoparticles, which makes the BST nanowires a better candidate as piezocatalyst. The catalytic nature of the stress induced dye degradation was confirmed by the detection of free radicals and intermediate products during the degradation process. The improvement of piezocatalytic efficiency in BST was attributed to a combined contribution of lower activation energy and higher polarization potential.