Sonochemical accelerated fabrication of MgIn2S4/COFs S-scheme heterojunction for efficient photocatalytic H2O2 production

Photocatalytic hydrogen peroxide (H₂O₂) production has garnered significant research interest for its environmental benefits and sustainability. S-scheme heterostructure incorporating covalent organic frameworks (COFs) has been recognized as an effective strategy for enhancing photocatalytic H₂O₂ performance. In this study, MgIn₂S₄/COFs (MIS/sonoTp-TAPB) S-scheme heterojunction were fabricated via a simple, rapid, and eco-friendly sonochemical method. High-frequency ultrasound induces cavitation effects, generating transient localized high temperatures and pressures, intense microjets, and enhanced mass transfer, effectively overcoming the limitations of conventional synthesis. This approach reduces solvent consumption, shortens reaction duration to 2 h, and ensures sufficient interface contact between MIS and sonoTp-TAPB. The as-obtained MIS/sonoTp-TAPB_0.05 heterojunction achieved a photocatalytic H₂O₂ production rate of 1610.54 μmol·g^-1·h^-1, which was 2.36 and 3.13 times higher than pristine MIS and sonoTp-TAPB, respectively. The S-scheme structure combines the redox capacity of both MIS and sonoTp-TAPB, and maintains a high H₂O₂ yield in pure water (1198.2 μmol·g^-1·h^-1). This enhancement is attributed to abundant surface-active sites, broadened optical absorption, and enhanced carrier separation resuting from S-scheme heterojunction between MIS and sonoTp-TAPB.