Narrow Results

Multiferroic Ba(Ti${}_{0.80}$Zr${}_{0.20}$)O₃-0.5(Ba${}_{0.70}$Ca${}_{0.30}$)TiO₃ (BCTZ)@CoFe₂O₄ (CFO) hybrid nanofibers (NFs) were fabricated by a sol–gel electrospinning. The perovskite structure of ferroelectric BCTZ and the spinel structure of ferromagnetic CFO coexist and are homogeneously distributed, and their interface along the perovskite [110] zone axis was directly observed. The indirect magnetoelectric (ME) coupling effect was observed from the magnetization versus temperature (M–T) curves, demonstrating a distinct singularity on the dM/dT curve near the ferroelectric Curie temperature ($T$${}_C$) of 387 K. The piezocatalytic rate of BCTZ@CFO multiferroic hybrid NF (2.6 × 10${}^{-2}$min${}^{-1}$) is higher than NP (1.9 × 10${}^{-2}$min${}^{-1}$) because the piezoelectricity of the one-dimensional (1D) multiferroic NF is higher than that of NPs, beneficial for the mechanical vibration-induced localized built-in electric fields for piezocatalysis under ultrasound.

Piezocatalysis is an emerging approach for degrading organic dye. However, the limited availability of ultrasonic resources in nature restricts its practical application. Our proposed peak flow kinetic energy piezocatalytic strategy, based on a “waterfall flow” model, aims to simulate the piezocatalytic degradation of pollutants in nature. This innovative strategy can enhance degradation efficiency by adjusting the flow rate and drop height. When 140mL of rhodamine B (RhB) dye solution flows at a rate of 1000mL/min from a height of 48cm and impacts a 3 cm diameter BaTiO₃ nanowires/PVDF piezoelectric composite film, a degradation rate of 90% can be achieved within 120min. This rapid degradation is primarily attributed to the efficient conversion of kinetic energy into impact force as the water falls, which triggers the generation of piezopotential in the composite film. This, in turn, drives the separation and transmission of electron–hole pairs, leading to the promotion of reactive oxygen species (ROS) generation and facilitating fast organic dye degradation. The pulsating nature of the impact force ensures a continuous generation of ROS. This approach is poised to advance piezocatalysis for the degradation of organic dyes in natural environments and presents a novel method for wastewater treatment.

Piezocatalysis has emerged as a promising environmental remediation technique, and the exploration of environmentally friendly and high-performance piezocatalysts is crucial for their practical applications. In this work, the bismuth sodium titanate (Na${}_{0.5}$Bi${}_{0.5}$TiO₃ (NBT)) exhibited efficient piezocatalytic activity toward typical organic pollutants degradation, including acid orange 7, methylene blue, rhodamine B and methyl orange. Notably, rhodamine B was degraded by 98.1% within 30min with a reaction rate constant of 0.130min${}^{-1}$. Furthermore, the NBT achieved a hydrogen peroxide production efficiency of 538$\mu$mol/g⋅h without the sacrificial agent, indicating that the NBT is a superior piezocatalyst for dye degradation and hydrogen peroxide generation. This work demonstrated that by using mechanical energy, the NBT can be used for degrading organic pollutants in wastewater and hydrogen peroxide generation.