Lead‐Free (K, Na)NbO₃ Piezocatalyst with Superior Piezocatalysis and Large‐Scale Production

Abstract

Although piezocatalysis has achieved preliminary achievements in environmental remediation and biomedical applications, large‐scale fabrication of piezocatalysts with high degradation efficiency and low cost remains challenging. In this work, a new and easy strategy to solve this challenge is innovatively proposed, that is, ceramic‐powder‐driven boosted polarization intensity, and validated the strategy is by examining potassium sodium niobate ((K, Na)NbO3, KNN) ferroelectric. KNN‐3 piezocatalyst, obtained by grinding as‐sintered ceramics into powder, shows a degradation rate (k) as high as 148 × 10−3 min−1 for rhodamine B (RhB) dye and for 31 × 10−3 min−1 for methyl orange (MO) dye, ≈18 times and 66 times than those of previously reported KNN piezocatalysts. The superior piezocatalytic activity is attributed to enhanced polarization intensity, increased oxygen vacancies, and higher charge carrier concentrations. Besides, the KNN‐3 piezocatalyst shows excellent inhibitory effects on Staphylococcus aureus and Escherichia coli strains. Therefore, the proven ceramic preparation technology enables the new strategy to mass produce high‐performance KNN piezocatalysts that hold promise for applications in dye degradation and biomedicine.

Large Piezoelectricity Induced by Internal Stress in (K,Na)NbO3 Single Crystals

“…Piezoelectric materials, with the superior function of energy conversion from mechanical form to electrical form or vice versa, have found extensive applications in the fields of sensing, medical ultrasound imaging, underwater communication, and other fields. − Among all of the piezoelectric materials, the ferroelectric family shows the most superior piezoelectric response, thereby attracting numerous research interests. Although ferroelectric materials vary, the core functions have always been to enable devices with excellent performance outputs within a wide operational range in numerous electromechanical applications; therefore ferroelectric materials with high piezoelectric response and excellent stability are highly required, , flourishing research of exploring the origin of ultrahigh piezoelectricity and improving its piezoelectric performance as well as stability. − Numerous strategies have been proposed to acquire large piezoelectricity in ferroelectric materials, including the constructions of multiphase coexistence, polar nanoregions (PNRs), and electric-field-induced phase transition, etc. ,− Among them, Pb-based relaxor ferroelectric crystals have made remarkable progress in the design, research, and application of ultrahigh piezoelectricity. ,,, However, lead-free ferroelectrics with high performance and excellent stability are preferred over Pb-based materials due to environmental issues.…”

Scalable synthesis of Bi2O2S nanoplates with large piezoelectric potential induced by a built-in electric field in a [Bi2O2]2+ layer for the degradation of organic contaminants

“…Up to now, a large number of 2D bismuth layer materials have obtained excellent piezoelectric catalytic activity because of their asymmetric and deformable structures. 14–17 Lately, BiOIO 3 , Bi 2 O 2 CO 3 , Bi 2 WO 6 and Bi 2 O 2 (OH)(NO 3 ) have aroused special interest owing to each of their crystal structures consisting of [Bi 2 O 2 ] 2+ fluorite-structure layers and intertwined halide ions or anionics. 18,19 The orderly layered structure is apt to form a BIEF and accomplish effective charge detachment, thus endowing these materials with exceptional piezoelectric catalytic activity.…”