CoP-Enhanced CaTiO₃ Single-Electron Oxygen Reduction Piezoelectric Catalysis for H₂O₂ Production

Piezoelectric catalytic production of H₂O₂ is a novel and environmentally friendly H₂O₂ production method, and many piezoelectric catalysts are currently being developed. However, all of them have the disadvantages of precious metals as cocatalysts and low catalytic efficiency. Herein, CaTiO₃ was successfully prepared and loaded with the nonprecious metal CoP (CoP/CaTiO₃) for piezoelectric catalytic production of H₂O₂. The yield of H₂O₂ produced by 5% CoP/CaTiO₃ piezoelectric catalysis reached 9657.3 μmol L^-1 g^-1, which was 1.64 times than that of single-component CaTiO₃, and furthermore, the performance remained stable after five cycles. This study directly demonstrates the piezoelectric response of CoP/CaTiO₃ by using Piezoresponse Force Microscopy. Under ultrasonic conditions, CoP/CaTiO₃ undergoes polarization, resulting in the generation of electrons (e^-) and holes (h⁺). The e^- undergoes a two-step single-electron reaction with O₂ to form H₂O₂. Because the conduction band position of CoP is lower than that of CaTiO₃, this potential difference promotes the migration of e^- from CaTiO₃ to CoP. This migration process effectively enhances the spatial separation of e^- and h⁺, which significantly improves the piezoelectric catalytic performance. In this work, a nontoxic and inexpensive new piezoelectric catalytic material was synthesized by a method that can produce catalysts in large quantities, and a strategy was provided to improve the piezoelectric catalytic activity, which played a key role in promoting the green industrial production of H₂O₂.