High photopiezocatalytic energy conversion via effective charge separation and deformability in the asymmetric ternary heterojunction Bi4Ti3O12/PPy/TiO2

Photopiezocatalysts can take advantage of both solar light and environmental mechanical energy, holding high significance in building a sustainable society. However, designing high potent photopiezocatalysts remains challenging. In this study, we propose the asymmetric ternary heterojunction as an efficient strategy for achieving effective photopiezocatalysts. The BTO/PPy/TiO2 catalyst composed of BaTiO3 (BTO) and TiO2 nanosheets and polypyrrole (PPy) nanoparticles present both enhanced asymmetric interfacial charge separation as well as deformability under mechanical stimuli, leading to appealing photopiezocatalytic capabilities. The d33 of the ternary BTO/PPy/TiO2 heterojunction is 3.1 times that of the binary BTO/TiO2 counterparts. In-situ synchrotron-radiation-IR measurements indicates that electric fields excite electrons to higher energy levels and lead to larger electron densities in the heterojunction. The piezoelectric fields also enhance charge separations. Using cycled assembly, the ternary BTO/PPy/TiO2 heterojunctions are facilely constructed on a copper mesh substrate, and its application in effective photopiezocatalytic degradation reactions are demonstrated. We expect the study elucidate the mechanism underlining efficient energy conversion and application in the photopiezocatalytically active asymmetric heterojunction and inspire the design of efficient catalysts.