Oxidation-enhanced piezocatalytic activity in carbon nitride-based catalysts for hydrogen and hydrogen peroxide production

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. Here, we report the construction of an oxidized carbon nitride (g-C3N4) matrix anchored with TiO2 nanoparticles via alkaline hydrothermal treatment. 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 CN-1BT 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 one hour 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.