Pyroelectric catalytic performance of Sm3+-modified Pb(Mg1/3Nb2/3)O3–PbTiO3 for organic dyes: degradation efficiency, kinetics and pyroelectric catalytic mechanism

Abstract

The development of photocatalysis is hindered, in part, by the quick recombination of photogenerated carriers and the instability of light sources. In this study, the problem of too-fast electron–hole pair compounding in photocatalysis is effectively regulated by the polarization field of pyroelectric materials using the pyroelectric method. Self-polarized pyroelectric materials that depend on temperature variations can generate usable electrical energy and polarized charge carriers to degrade organic pollutants. Pb(Mg_1/3Nb_2/3)O₃–PbTiO₃ (PMN–PT) is a relaxor ferroelectric material with spontaneous polarization characteristics. The PMN–0.30PT:1 mol%Sm³⁺ catalyst was prepared by applying the high-temperature solid-state reaction method. Under the dark condition and nine cold–hot cycles of 23 °C–68 °C, using H₂O₂-assisted PMN–0.30PT:1 mol%Sm³⁺ as a catalyst, the degradation rate of rhodamine 6G (10 mg L⁻¹) was 94.3 ± 2.5%. In addition, the degradation rates of 88.52% and 64.32% were obtained for rhodamine B (10 mg L⁻¹) and methylene blue (10 mg L⁻¹), respectively. This study provides a new approach to the pyroelectric catalytic degradation of organic pollutants.