Boosting Piezo‐Catalytic Activity of KNN‐Based Materials with Phase Boundary and Defect Engineering

Abstract Although the piezo‐catalysis is promising for the environmental remediation and biomedicine, the piezo‐catalytic properties of various piezoelectric materials are limited by low carrier concentrations and mobility, and rapid electron‐hole pair recombination, and reported regulating strategies are quite complex and difficult. Herein, a new and simple strategy, integrating phase boundary engineering and defect engineering, to boost the piezo‐catalytic activity of potassium sodium niobate ((K, Na)NbO 3 , KNN) based materials is innovatively proposed. Tur strategy is validated by exampling 0.96(K 0.48 Na 0.52 )Nb 0.955 Sb 0.045 O 3 ‐0.04(Bi x Na 4‐3 x ) 0.5 ZrO 3 ‐0.3%Fe 2 O 3 material having phase boundary engineering and conducted the defect engineering via the high‐energy sand‐grinding. A high reaction rate constant k of 92.49 × 10 −3 min −1 in the sand‐grinding sample is obtained, which is 2.40 times than that of non‐sand‐grinding one and superior to those of other representative lead‐free perovskite piezoelectric materials. Meanwhile, the sand‐grinding sample has remarkable bactericidal properties against Escherichia coli and Staphylococcus aureus. Superior piezo‐catalytic activities originate from the enhanced electron‐hole pair separation and the increased carrier concentration. This study provides a novel method for improving the piezo‐catalytic activities of lead‐free piezoelectric materials and holds great promise for harnessing natural energy and disease treatment.