Unconstrained Coordination of Pt Single Atoms on Distorted g-C₃N₄ Enables Electronic Flexibility and Enhanced...

The accumulation of microplastic waste has raised growing environmental concerns, motivating the development of sustainable strategies for plastic-to-fuel conversion. Here, we report a platinum single-atom catalyst anchored on distorted graphitic carbon nitride (Pt₁/CN) for efficient photocatalytic microplastics photoreforming. Unlike conventional planar g-C₃N₄ models, the locally distorted heptazine framework introduces off-plane coordination environments that enable unconstrained Pt─N coordination and promote electronic flexibility. X-ray absorption spectroscopy reveals Pt─N coordination associated with distorted heptazine units, where distortion-induced charge localization enhances interfacial electron transfer to Pt sites. In situ measurements under light irradiation further confirm efficient charge transfer at the Pt₁/CN interface. Among various microplastics, polyethylene terephthalate (PET) exhibits the highest hydrogen evolution rate of 533.18 µmol·g^-1·h^-1, attributed to alkaline-assisted ester bond cleavage. Density functional theory calculations demonstrate that Pt single atoms facilitate hydrogen evolution by lowering H⁺ reaction barrier and stabilizing key intermediates. This work elucidates the structure-activity relationship of Pt₁ in polymeric semiconductors and establishes a framework-level design strategy for electronic flexibility in photocatalytic plastic-to-fuel conversion.