The efficient synthesis of hydrogen peroxide (H₂O₂) through piezo-photocatalysis is a promising yet challenging sustainable route, primarily limited by inefficient charge separation and sluggish surface reaction kinetics. This study introduces an innovative bi-ionic (K⁺/Ca²⁺) co-doping strategy to engineer graphitic carbon nitride, creating a high-performance catalyst for H₂O₂ production. The bi-ionic doping structure, combined with introduced cyano groups, constructs multi-charge transfer channels and significantly enhances the piezoelectric polarization field, which dramatically promotes the directional separation and migration of photogenerated charge carriers. More importantly, the Ca²⁺ sites and adjacent N-cyano groups form synergistic Frustrated Lewis pairs, which simultaneously facilitate spontaneous ethanol dissociation to supply protons and strongly adsorb and activate O₂ molecules. Consequently, the optimized catalyst shows an exceptional piezo-photocatalytic H₂O₂ production rate of 24.95 mmol g^？1 h^？1 under visible light and ultrasound, significantly outperforming most reported analogues. Furthermore, we fabricated shape-tunable hydrogels by integrating the catalyst with Sil-MA, which not only facilitates catalyst recovery but also creates a beneficial gas-solid interface when coated on floating substrates. The floating hydrogel system maintains stable H₂O₂ production, demonstrating great potential for practical applications. This work provides valuable insights into designing efficient piezo-photocatalytic systems for sustainable chemical synthesis.

Article link: https://doi.org/10.1002/adfm.77014