Single‐Atom Photocatalyst as Floatable Artificial Leaf for Upcycling Oceanic Plastic Waste

ABSTRACT Over ∼8 billion tons of plastic have been produced to date, with ∼80% of them ended up in landfills/oceans. Among them, polypropylene (PP) possesses the lowest global recycling rate (< 1%). To resolve this, Ru single atoms (SAs) loaded photocatalysts (ZnIn 2 S 4 /Ru SAs) in the forms of powder/floatable artificial leaf (AL) were prepared for direct conversion of raw PP plastic into valuable chemicals. The optimized photocatalyst exhibits exceptional performance with a total formic/acetic acid production of 1022.5 µmol g −1 . In situ X‐ray photoelectron spectroscopy, in situ atomic force microscopy‐kelvin probe force microscopy, and in situ electron paramagnetic resonance (EPR) reveal efficient electron extraction from ZnIn 2 S 4 nanosheets to Ru SAs, with subsequent electron capture by O 2 molecules in air. Additionally, in situ transient‐state photoluminescence spectroscopy, transient photovoltage measurement, and in situ EPR unveil the electrolyte‐assisted polarization (induced by cations/anions in seawater) significantly enhancing charge separation/transfer. Finally, in situ EPR, in situ infrared (IR) spectroscopy, and quenching experiments corroborate the pivotal roles of reactive oxygen species (·O 2 − /·OH) for upcycling PP into valuable chemicals. These results highlight the transformative potential of floatable AL concept for converting plastic waste into high‐value chemicals, offering a sustainable solution to plastic contamination.