Dynamic Internal Field Engineering in BaTiO₃-TiO₂ Nanostructures for Photocatalytic Dye Degradation

Ferroelectric-semiconductor nanostructures can exhibit enhanced photocatalytic activity benefiting from charge separation and transport facilitated by a spontaneous polarization-induced electric field. However, this static electric field can be easily compensated, thus hindering enhancement of photocatalysis. In this study, we propose to introduce a consecutive periodic thermal variation into BaTiO3-TiO2 nanostructures to achieve excellent photocatalysis via dynamic internal field engineering based on the pyroelectric effect of BaTiO3. The theoretical simulation reveals that spontaneous polarization of BaTiO3 can be changed with temperature, which in consequence varies strength and distribution of the polarization-induced electric field, leading to the formation of a dynamic internal field in the BaTiO3-TiO2 nanostructures. Experimental evidence proved that the dynamic internal field facilitated by the consecutive thermal variation can function for incessant charge separation and transport as well as accelerated catalytic reactions over the BaTiO3-TiO2 nanostructures, thereby resulting in significantly improved degradation efficiency with a remarkable cyclic ability.