Synergistic Enhancement of Photocatalytic H₂O₂ Production over Carbon Nitride Oxide/Biochar Composites

The green synthesis of hydrogen peroxide (H₂O₂) is crucial for sustainable chemical production, but pristine graphitic carbon nitride (g-C₃N₄) suffers from low H₂O₂ yield owing to limited visible light absorption and swift charge recombination. Herein, a novel metal-free carbon nitride oxide/biochar photocatalytic system (CNO-B) was developed via a simple low-temperature calcination without post-treatment. The synergistic effect of carbonyl functionalization and biochar integration significantly enhanced light harvesting capabilities and charge carrier separation efficiency, achieving an exceptional H₂O₂ production rate of 2483 μmol g^-1 h^-1 upon irradiation (five times higher compared with pure g-C₃N₄). This work provides valuable insights into minimalist synthesis strategies for designing functional materials and demonstrates a practical approach for valorizing biomass waste in sustainable photocatalytic applications.