Enhanced Sunlight-Driven Reactive Species Generation via Polarization Field in Nanopiezoelectric Heterostructures

Abstract

Although it is established that the force-induced electric polarization field of piezoelectric semiconductors can be used to tune the transfer rate of photoexcited charge carriers, there is still a lack of successful strategies to effectively improve the photocatalytic reactivity and solar-to-chemical conversion efficiency (SCC) of piezoelectric materials. Here, we are the first to prepare and study a kind of catalyst based on nanopiezoelectric heterostructures of LiNbO3-type ZnTiO3·TiO2 and tetragonal BaTiO3 with Pt or FeO x nanoparticle modification (i.e., ZBTO–Pt or ZBTO–FeO x ) for reactive species generation. With respect to the production of •OH and •O2 – radicals, higher amounts were observed in piezophotocatalysis relative to those for individual piezo- and photocatalysis. Benefiting from the charge transfer resistance decreases by the deposition of Pt and FeO x , the amounts of •OH radicals formed on ZBTO–Pt and ZBTO–FeO x were approximately 48 and 21% higher than that on isolated ZBTO during piezophotocatalysis, and for the amounts of •O2 – radicals the enhancements were approximately 11 and 6%, respectively. Furthermore, the concentrations of H2O2 formed on ZBTO–Pt and ZBTO–FeO x under piezophotocatalysis reached approximately 315 and 206 μM after 100 min of reaction (and was still increasing) corresponding to 0.10 and 0.06% SCCs, respectively, which were also much higher than the concentrations and SCCs observed for piezo- and photocatalysis. The enhancements of piezophotocatalytic activities with these piezoelectric materials were related to the mechanical strain exerted on ZBTO, which generated a larger electric polarization field than those on ZnTiO3·TiO2 and BaTiO3 as analyzed by a finite element method. This high-intensity electric polarization field accelerated the separation and transportation of photoexcited charge carriers in the highly sunlight responsive nanopiezoelectric heterostructures based on ZBTO–Pt and ZBTO–FeO x .

Doxycycline detection and degradation in aqueous media via simultaneous synthesis of Fe-N@carbon dots and Fe3O4-carbon dot hybrid nanoparticles: a one arrow two hawk approach

“…The application of cavitation force gives mechanical stress to the material, which drives free charge carriers (e − + h + ) to the surface. 72–74 These e − and h + react with OH − and O 2 present in the system to produce ROS (˙OH/˙O 2 ) as described in the following eqn (3)–(12).Fe 3 O 4 + cavitation cum shear force → e − + h + OH − + h + → ˙OHO 2 + e − → O 2 − 2e − + 2H + + O 2 → H 2 O 2 H 2 O 2 + e − + H + → OH − + ˙OH…”

“…The application of cavitation force gives mechanical stress to the material, which drives free charge carriers (e À + h + ) to the surface. [72][73][74] These e À and h + react with OH À and O 2 present in the system to produce ROS ( OH/ O 2 ) as described in the following eqn (3)- (12).…”

Biofilm Microenvironment-Sensitive Piezoelectric Nanomotors for Enhanced Penetration and ROS/NO Synergistic Bacterial Elimination

“…The piezoelectric effect and distribution of the electric field were simulated by COMSOL Multiphysics software . The model consisted of tetragonal BT NPs with a diameter of 120 nm.…”

“…The piezoelectric effect and distribution of the electric field were simulated by COMSOL Multiphysics software. 25 The model consisted of tetragonal BT NPs with a diameter of 120 nm. In piezoelectric devices, the modules defining the polarization of NPs model were aligned along the z axis, while the central plane was fixed perpendicularly to the z axis and grounded.…”