Piezoelectric-catalytic degradation of organic dyes and catalytic reduction of Cr(VI) with BaCO3@BaTiO3 microspheres

Abstract

Piezoelectric-catalytic degradation of organic and inorganic pollutants is an important feasible and green treatment method. In this study, novel BaCO3@BaTiO3 microspheres have been fabricated firstly by the hydrothermal-calcination method, and a variety of physical and chemical characterization and surface analysis methods, such as X-ray diffraction (XRD), Fourier-transform infrared spectroscopy (FT-IR), scanning electron microscope (SEM), X-ray photoelectron spectroscopy (XPS), and Brunauer-Emmett-Teller (BET) analyses have been carried out. The piezoelectric-catalytic activity of the as-prepared composites has been also evaluated through the degradation of organic pollutants (Rhodamine B and Methylene blue) and catalytic reduction of heavy metal ions (Cr(VI)) with the help of ultrasound. The catalytic mechanism shows that the active substances for the catalytic degradation of dyes are hydroxyl radicals (•OH) and superoxide radicals (•O2−), and the active species that catalytically reduces Cr(VI) to Cr(III) is mainly the electrons (e−) produced by the separation of electron-hole pairs induced by mechanical force. The as-prepared microspheres catalyst has high piezoelectric-catalytic degradation ability and good catalytic cycle stability, which is a kind of green wastewater treatment catalyst with practical application prospect.