Acid-induced morphological engineering of g-C3N4 for enhanced piezocatalytic hydrogen peroxide synthesis

Abstract

Piezocatalysis for hydrogen peroxide (H₂O₂) production offers an eco-friendly alternative to the conventional anthraquinone method, addressing its high energy consumption and toxic byproducts. However, the core challenge lies in the suboptimal performance of existing piezocatalysts, necessitating modifications to enhance H₂O₂ yield. This study proposes and demonstrates that a facile hydrochloric acid pretreatment of melamine can effectively enhance the performance of as-derived graphitic carbon nitride (g-C₃N₄) in piezocatalytic H₂O₂ production. Distinct from previous acid-treatment strategies that primarily focused on surface area expansion for photocatalysis, our work highlights the critical role of morphology engineering in overcoming the poor structural deformability of bulk g-C₃N₄, thereby improving its piezocatalytic performance. Results indicate that acid pretreatment transforms bulk g-C₃N₄ into a flake-like structure while preserving its crystal structure, resulting in a notably enhanced piezocatalytic H₂O₂ yield of 793 μmol g⁻¹ h⁻¹, nearly doubling that of the pristine bulk counterpart. This improvement is attributed to the superior deformability of the flake-like structure, which effectively amplifies the piezopotential and further boosts the catalytic activity. Mechanism studies suggest that ·OH and ¹O₂ play important roles in piezocatalytic H₂O₂ production, with holes (h⁺) and ·O₂⁻ also being involved in the reaction process. This research offers a feasible approach for simple modification of g-C₃N₄ towards efficient piezocatalysis.