CoP-Enhanced CaTiO<sub>3</sub> Single-Electron Oxygen\nReduction Piezoelectric Catalysis for H<sub>2</sub>O<sub>2</sub> Production

Piezoelectric\ncatalytic production of H<sub>2</sub>O<sub>2</sub> is a novel and\nenvironmentally friendly H<sub>2</sub>O<sub>2</sub> production method,\nand many piezoelectric catalysts are currently\nbeing developed. However, all of them have the disadvantages of precious\nmetals as cocatalysts and low catalytic efficiency. Herein, CaTiO<sub>3</sub> was successfully prepared and loaded with the nonprecious\nmetal CoP (CoP/CaTiO<sub>3</sub>) for piezoelectric catalytic production\nof H<sub>2</sub>O<sub>2</sub>. The yield of H<sub>2</sub>O<sub>2</sub> produced by 5% CoP/CaTiO<sub>3</sub> piezoelectric catalysis reached\n9657.3 μmol L<sup>–1</sup> g<sup>–1</sup>, which\nwas 1.64 times than that of single-component CaTiO<sub>3</sub>, and\nfurthermore, the performance remained stable after five cycles. This\nstudy directly demonstrates the piezoelectric response of CoP/CaTiO<sub>3</sub> by using Piezoresponse Force Microscopy. Under ultrasonic\nconditions, CoP/CaTiO<sub>3</sub> undergoes polarization, resulting\nin the generation of electrons (e<sup>–</sup>) and holes (h<sup>+</sup>). The e<sup>–</sup> undergoes a two-step single-electron\nreaction with O<sub>2</sub> to form H<sub>2</sub>O<sub>2</sub>. Because\nthe conduction band position of CoP is lower than that of CaTiO<sub>3</sub>, this potential difference promotes the migration of e<sup>–</sup> from CaTiO<sub>3</sub> to CoP. This migration process\neffectively enhances the spatial separation of e<sup>–</sup> and h<sup>+</sup>, which significantly improves the piezoelectric\ncatalytic performance. In this work, a nontoxic and inexpensive new\npiezoelectric catalytic material was synthesized by a method that\ncan produce catalysts in large quantities, and a strategy was provided\nto improve the piezoelectric catalytic activity, which played a key\nrole in promoting the green industrial production of H<sub>2</sub>O<sub>2</sub>.