Photogenerated hole-mediated oxi-upcycling of polyethylene to dicarboxylic acids over a waste plastic-derived MIL-101(Cr)

Waste PET-derived MIL-101(Cr) enables polyethylene oxidation. • Photogenerated holes directly participate in PE C–H activation. • A thermally assisted photoinduced oxidation pathway is established. • Polyethylene is converted into recoverable dicarboxylic acids. • Cross-polymer valorization integrates PET and PE waste streams. Heterogeneous catalytic oxidation of polyethylene (PE) into dicarboxylic acids remains challenging because of the difficulty in activating chemically inert C–H bonds. Here, we report a waste polyethylene terephthalate (PET)-derived MIL-101(Cr) photothermal catalyst that enables photogenerated hole ( h + )-driven activation of PE during oxidation. Under 130 °C, 1.0 MPa O 2 , and 370 mW cm −2 light irradiation, complete conversion of PE is achieved, affording aliphatic dicarboxylic acids (C4-C22) with a carbon yield of up to 63.7 wt%. Experimental and theoretical investigations reveal that photogenerated h + directly activate C–H bonds of surface-adsorbed PE through hydrogen abstraction, thereby initiating the oxidation process. The carboxylate ligands on the MIL-101(Cr) surface promote favorable interfacial interactions with PE chains, facilitating effective catalyst-polymer contact for interfacial C–H bond activation. This work provides new mechanistic insights into heterogeneous photothermal PE oxidation and offers new guidance for catalyst design based on photogenerated h + oxidation. Download: Download high-res image (246KB) Download: Download full-size image