Enhancement of piezocatalytic activity at the ferro-paraelectric phase transition of Ba1-xSrxTiO3 nanopowders

Nanocrystalline Ba1-xSrxTiO3 (x = 0-0.3) powders were investigated with special interest in their piezocatalytic performance for degradation of organic pollutants. A great improvement of piezocatalytic activity was obtained for the compositions x = 0.2, in which the polarization shows a large change under external stress. Furthermore, with the increase of working environment temperature, the piezocatalytic performance of Ba0.8Sr0.2TiO3 increases firstly and then decreases, giving the best piezocatalytic performance near its Curie temperature. For a better understanding of the piezocatalytic mechanism, the dynamics of charge carriers transfer on solid/liquid interface was discussed with respect to activation energy and overpotential of catalyst. It was suggested that the enhanced piezocatalytic activity of Ba1-xSrxTiO3 comes from two aspects: (1) the overpotential provided by the piezoelectric effect decreases with the increasing Sr content, (2) the activation energy for the piezocatalytic reaction is greatly reduced at ferro-paraelectric phase transition. Combination of these two aspects gives rise to the nonlinear dependence of piezocatalytic activity on Sr content. (C) 2021 Elsevier Ltd. All rights reserved.

Automated summary

Nanocrystalline Ba1-xSrxTiO3 powders exhibit enhanced piezocatalytic activity, with compositions x = 0.2 showing the best performance. The piezocatalytic activity of Ba0.8Sr0.2TiO3 is found to increase initially and then decrease with increasing temperature, peaking near its Curie temperature. The mechanism is suggested to be influenced by both the Sr content and the activation energy at ferro-paraelectric phase transition.