Bi ₄ Ti ₃ O ₁₂ Nanoplates with Engineered Bi ^{3 <b>+</b>} Vacancies for Enhanced Reactive Oxygen Species Generation and Neuroregeneration

Piezocatalysis driven by mechanical vibration has emerged as a promising approach for environmental remediation and biomedical therapy. Nevertheless, achieving a high catalytic efficiency through rational material design remains a critical challenge. Herein, different from the extensively studied oxygen vacancy strategy, we report a novel cation defect-engineering strategy for the dual enhancement of catalytic and neuro-regenerative performance. This study demonstrates, for the first time, that bismuth vacancies (VBi) act as powerful active sites that modulate the electronic structure and charge transfer dynamics, resulting in remarkable catalytic enhancement and neuronal differentiation capability. Compared with VBi deficient Bi4Ti3O12, VBi-rich Bi4Ti3O12 nanoplates exhibit substantially enhanced piezocatalytic activity, with a 1.7-fold increase in •O2¯ concentration, a 4-fold increase in •OH concentration, and a 17-fold increase in the reaction rate constant. Density functional theory (DFT) calculations reveal that VBi introduces an intermediate defect energy level within the bandgap, thereby facilitating charge separation and reactive species generation. Moreover, under ultrasonic–piezoelectric stimulation, the VBi-rich nanoplates significantly promote neuronal differentiation, underscoring their dual functionality in catalytic and biomedical applications. Collectively, this study provides comprehensive insights into the critical role of cation defect engineering in advancing high-performance piezoelectric materials, thereby establishing a novel and effective paradigm for both environmental remediation and neuronal regenerative applications.