Incorporation of hydroxyl groups and π-rich electron domains into g-C3N4 framework for boosted sacrificial agent-free photocatalytic H2O2 production

•Tartrate-modified carbon nitride (TA-CN) was synthesized via solution pyrolysis.•TA-CN is abundantly endowed with π-electron-rich domains and hydroxyl groups.•π-rich electron domain in CN matrix increase active sites in TA-CN nanosheets.•Hydroxyl groups in TA-CN boost charge carrier migration to oxygen-containing groups.•Hydroxyl groups enhance TA-CN hydrophilicity, reducing H2O2 self-decomposition rate. Photocatalytic synthesis of hydrogen peroxide (H2O2) based graphitic carbon nitride (g-C3N4) materials has garnered significant attention due to its green and sustainable attributes. In this study, g-C3N4 nanosheets enriched with π‑rich electron domains and hydroxyl groups were synthesized through the pyrolysis of urea-tartaric acid mixed solution, and subsequently utilized for efficient photocatalytic production of H2O2. The incorporation of π-rich electron domains induced a downward shift in the conduction band edge, which can significantly diminish the Coulombic interactions of singlet Frenkel excitons, thereby facilitating efficient photo-generated charge separation and accelerated charge migration. Simultaneously, the modification with hydroxyl groups in g-C3N4 network enhances water molecule adsorption, reducing side reactions and thereby increasing the efficiency of selective H2O2 generation. The integration of π-rich electron domains with hydroxyl groups in g-C3N4, along with a comprehensive understanding of their underlying mechanisms, provides valuable insights for the rational design and synthesis of highly active energy conversion catalytic materials.