As a leading Pb-free perovskite material (ABO₃-type), potassium sodium niobate (K,Na)NbO₃ (KNN)-based ferroelectrics/piezoelectrics have been widely used in electronics, energy conversion, and storage due to their exceptional ability to interconvert mechanical and electrical energies. Beyond traditional applications, the piezoelectric potential generated by mechanical strain or stress modifies their energy band structures and facilitates charge carrier separation and transport, drawing increasing attention in emerging fields such as piezocatalysis and photo-piezocatalysis. With excellent piezoelectric properties, chemical/thermal stability, and strain-tuning capability, KNN-based materials show great promise for high-performance piezocatalytic applications. Coupling KNN with semiconductors exhibiting strong optical absorption to form heterojunctions further boosts performance by suppressing electron–hole recombination and promoting directed charge transfer, which is crucial for photo-piezocatalysis. The flexibility of KNN's perovskite structures also allows for modifications in chemical composition and crystal structure, enabling diverse design strategies such as defect engineering, phase boundary engineering, morphology control, and heterojunction formation. This review comprehensively explores the recent advancements in KNN-based piezocatalysis and photo-piezocatalysis, starting with an overview of their crystal structures and intrinsic properties. It then explores the role of piezoelectric potential in charge carrier dynamics and catalytic activity, followed by strategic design approaches to optimize efficiency in environmental remediation and energy conversion. Finally, the review addresses current challenges and future research directions aimed at advancing sustainable solutions using KNN-based materials in these applications.

中文翻译：

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用于高性能压电催化和光压电催化的新兴 （K，Na）NbO3 钙钛矿的战略设计


作为领先的无铅钙钛矿材料 （ABO₃ 型），铌酸钾钠 （K，Na）NbO₃ （KNN） 基铁电体/压电体因其卓越的机械能和电能相互转换能力而被广泛用于电子、能源转换和存储。除了传统应用外，机械应变或应力产生的压电势改变了它们的能带结构，促进了载流子的分离和传输，在压电催化和光压电催化等新兴领域引起了越来越多的关注。KNN 基材料具有出色的压电性能、化学/热稳定性和应变调节能力，在高性能压电催化应用中显示出巨大的前景。将 KNN 与表现出强光吸收的半导体耦合以形成异质结，通过抑制电子-空穴复合和促进定向电荷转移来进一步提高性能，这对于光压电催化至关重要。KNN 钙钛矿结构的灵活性还允许修改化学成分和晶体结构，从而实现多种设计策略，例如缺陷工程、相边界工程、形态控制和异质结形成。本文全面探讨了基于 KNN 的压电催化和光压电催化的最新进展，首先概述了它们的晶体结构和本征性质。然后，它探讨了压电势在电荷载流子动力学和催化活性中的作用，然后介绍了优化环境修复和能源转换效率的战略设计方法。 最后，该综述讨论了当前的挑战和未来的研究方向，旨在在这些应用中使用基于 KNN 的材料推进可持续解决方案。