A Floatable S-Scheme S-pCN/BiVO₄/HPU-PGG System Forming the Three-Phase Interface to Promote High-Efficiency H₂O₂...

Achieving high solar-to-chemical conversion (SCC) efficiency is imperative for the practical application of semiconductors photocatalytic H₂O₂ production. However, this objective remains significantly challenging due to limitations inherent in conventional systems, including inefficient light harvesting, rapid charge recombination, and mass transfer constraints. To address these bottlenecks, a synergistic "material-system" design is validated. At the material level, ultraviolet-visible, X-ray photoelectron spectroscopy, and time-resolved photoluminescence analyses confirm that the S-pCN/BiVO₄ S-scheme heterojunction significantly broadens visible light absorption and facilitates directed charge separation. At the system level, contact angle and kinetic analyses demonstrate that anchoring the catalyst onto a hydrophilic polyurethane-poly (propylene glycol) (HPU-PGG) hydrogel creates a floatable platform with a three-phase interface, enabling direct atmospheric oxygen utilization and superior mass transfer. Furthermore, the system's physical architecture effectively isolates the photocatalyst from the H₂O₂ product, suppressing undesirable decomposition. Consequently, the S-pCN/BiVO₄/HPU-PGG system achieves a high H₂O₂ yield of 488μmol/L/h under visible light irradiation. This synergistic design achieves an SCC efficiency of 0.85%, which is eight times higher than that of natural photosynthesis.