Effective Coupling of Piezoresponse and Surface Catalysis over Core‐Shell BiOCl@BiPO ₄ Nanoplate Toward Enhanced Piezocatalytic O ₂ Reduction into H ₂ O ₂

Abstract Piezocatalytic O ₂ reduction into H ₂ O ₂ offers a convenient and sustainable solution for environmental remediation. However, the limited coupling between piezoresponse and surface catalysis constrains the performance. Herein, with bismuth oxychloride (BiOCl) as the model piezocatalyst, elaborate acid site engineering is employed to construct active sites on the surface where the piezopotential is located. The core‐shell BiOCl@BiPO ₄ nanoplate obtained by surface phosphorylation provides sufficient Lewis acid (Bi ³⁺ ) and Brønsted acid (PO ₄ ³⁻ ) sites for O ₂ activation and conversion. Moreover, the interfacial electric field at the heterojunction not only improves the piezoresponse behavior and accelerates carrier dynamics but also exhibits positive feedback on the surface acidity. Consequently, the contribution of piezopotential to O ₂ reduction over BiOCl@BiPO ₄ is optimized, achieving a piezocatalytic H ₂ O ₂ production rate of 884.7 µmol g ⁻¹ h ⁻¹ , which outperforms that of BiOCl (392.6 µmol g ⁻¹ h ⁻¹ ) and BiPO ₄ (558.3 µmol g ⁻¹ h ⁻¹ ). This study points out the importance of effective coupling between piezoresponse and surface catalysis for enhancing piezocatalytic performance, and also provides valuable insights into the precise functionalization of piezocatalysts.