Sm-doped Pb(Mg1/3Nb2/3)O3-xPbTiO3 piezocatalyst: Exploring the relationship between piezoelectric property and piezocatalytic activity

The piezocatalytic performance of Sm-doped Pb(Mg1/3Nb2/3)O3-xPbTiO3 solid solutions, which exhibit ultrahigh piezoelectric coefficient with a dependence on PbTiO3 content, was thoroughly investigated. We focused mainly on the influence of piezoelectric property modulation on the piezocatalytic performance of the materials by composition arrangement. The maximal piezocatalytic activity was achieved as the composition approached the morphotropic phase boundary (MPB) at x = 0.29, in which the piezoelectric coefficient also reached the maximum. The linear relationship between the two properties proves that the piezoelectric effect plays a key role in the piezocatalytic performance. As a direct evidence of catalytic reactions, free radicals were detected by electron spin resonance (ESR) technique. Revolution of intermediate products observed by liquid chromatography-mass spectrometry (LC–MS) further confirms the catalytic reactions in the piezoelectricity induced dye degradation process. This work is of great significance for understanding the mechanism of piezocatalytic effect.