A fingerprint-like supramolecular-assembled Ag₃PO₄/polydopamine/g-C₃N₄ heterojunction nanocomposite for enhanced...

Biocompatible photocatalytic water-splitting systems are promising for tissue self-oxygenation. Herein, a structure-function dual biomimetic fingerprint-like silver phosphate/polydopamine/graphitic carbon nitride (Ag₃PO₄/PDA/g-C₃N₄) heterojunction nanocomposite is proposed for enhanced solar-driven oxygen (O₂) evolution in vivo in situ. Briefly, a porous nitrogen-defected g-C₃N₄ nanovoile (CN) is synthesized as the base. Dopamine molecules are controllably inserted into the CN interlayer, forming PDA spacers (4.28 nm) through self-polymerization-induced supramolecular-assembly. Ag₃PO₄ nanoparticles are then in situ deposited to create Ag₃PO₄/PDA/CN. The fingerprint-like structure of PDA/CN enlarges the layer spacing, thereby accelerating mass transfer and increasing reaction sites. The PDA spacer roles as excellent light harvester, electronic-ionic conductor, and redox pair through conformational changes, resulting in tailored electronic band structure, optimized carrier behavior, and reduced electrochemical impedance. In physiological conditions, Ag₃PO₄/PDA/CN exhibits O₂ evolution rate of 45.35 μmol⋅g^-1⋅h^-1, 9-fold of bulk g-C₃N₄. The biocompatibility and in vivo oxygen supply effectiveness for biomedical applications have been verified in animal models.