The highly efficient degradation and purification of organic pollutants in wastewater by photocatalysis is still challenging. In this study, a piezoelectric potential-activated interfacial electric field (IEF) was constructed to endow BiFeO₃@BaTiO₃ (BFO@BTO) heterojunction with the ability to serve as a round-the-clock photocatalyst for polluted water remediation. BFO@BTO heterojunction is composed of BiFeO₃ nanoparticles decorated on the surface of BaTiO₃ nanorods, which shortens the carrier migration path. More importantly, the IEF can be activated and reconstructed under ultrasonic wave irradiation, leading to a lower potential barrier and enhanced separation efficiency for photogenerated carriers. The degradation rate constant k value of BFO@BTO heterojunction reached 0.038 min⁻¹, which was 1.9 and 7.0 times greater than that of piezocatalysis and photocatalysis alone, respectively. It also exhibited excellent stability in three light‒dark cycles for high concentrations (25 mg·L⁻¹) of rhodamine B (RhB) and tetracycline hydrochloride (TC). This study provides a promising strategy for designing highly active photoassisted piezocatalysts for environmental energy utilization and round-the-clock catalysis.

Photocatalytic hydrogen production is constrained by technical bottlenecks, such as narrow light absorption range of the catalyst and low catalyst activity. Photocatalytic piezoelectric composite BaTiO₃@TiO₂ nanoflowers were synthesized by using a simple hydrothermal method. The structure and morphology were characterized by using XRD, SEM and TEM, while the effect of stirring speed on photocatalytic hydrogen precipitation performance of the composites was deeply studied by using stirring as the external pressure. It is observed that TiO₂ was tightly anchored on surface of the BaTiO₃ nanospheres, whereas a close-contact type Ⅱ energy band structure was established. The BaTiO₃@TiO₂-1.2 sample exhibited a hydrogen precipitation rate of as high as 45.48 µmol·g^-1·h^-1, at a stirring rotational speed of 900 r·min^-1, which was higher than that at a low rotational speed (300 r·min^-1) by 7.19 times. The excellent photocatalytic hydrogen precipitation performance can be attributed to the repeated changes of piezoelectric field that has promoted the photogenerated carrier transfer and charge separation.

Silicon anode material becomes one of the ideal materials for high energy density lithium-ion battery, due to its low cost, high specific capacity and reliable safety. However, severe volume expansion during lithium embedding, poor material conductivity and poor cycling stability limit the commercial application of silicon anode material. Therefor, agar-derived carbon/NH₄F@nanosilicon composites (Si@FNC) were prepared by using a one-pot sol-gel method with agar and NH₄F to realize carbon coating and doping modification. Structure, morphology and electrochemical properties of the Si@FNC composites were studied. Cyclic stability and electrical conductivity of the Si@FNC composites were significantly improved after NH₄F modification. When the mass ratio of NH₄F to Si was 1:5, the first discharge specific capacity was 2001.0 mAh·g^-1 at a current density of 500 mA·g^-1, while the residual capacity was still maintained at 836.7 mAh·g^-1 after 200 cycles. The results could be used as a reference for further exploration of high-capacity silicon-carbon anode materials.