By harvesting mechanical energy through piezocatalysis, the oxidized g-C₃N₄ loaded with TiO₂ can directly split pure water into H₂ or H₂O₂. The composite achieves a remarkable H₂ production rate of 4427.2 μmol g⁻¹ h⁻¹ and H₂O₂ production rate of 809.3 μmol g⁻¹ h⁻¹.

Driven by the urgent need for a green, safe, and cost-effective approach to producing H₂ and H₂O₂—both highly valuable in green energy and environmental protection fields—piezocatalysis, which converts mechanical energy into valuable chemicals, has emerged as a promising solution. However, current catalyst systems face challenges due to the need for materials with both a strong piezoelectric effect and favorable catalytic activity. Herein, the construction of an oxidized carbon nitride (g-C₃N₄) matrix anchored with TiO₂ nanoparticles via alkaline hydrothermal treatment is reported. Under ultrasonication, the g-C₃N₄/TiO₂ composite exhibits optimal performance under carefully controlled alkaline hydrothermal conditions. With a low concentration of Ba(OH)₂ during hydrothermal treatment, Ba(OH)₂ provides an alkaline medium, oxidizing the g-C₃N₄ species and introducing structural defects into the g-C₃N₄ framework. The disruption of the g-C₃N₄ matrix, along with its interaction with TiO₂ nanoparticles, enhances the piezoelectric effect. Consequently, the oxidized g-C₃N₄/TiO₂ composite achieves a remarkable H₂ production rate of 4427.2 μmol g⁻¹ and an H₂O₂ production rate of 809.3 μmol g⁻¹ within 1 h without the addition of any sacrificial agents or cocatalysts. This work presents an effective strategy for the structural optimization of g-C₃N₄-based materials and may inspire new approaches for designing advanced piezocatalysts.