Chlorine Ion-Enhanced Efficient Photocatalysis of Polyethylene Plastics

Polyolefins such as polyethylene represent one of the most significant environmental hazards nowadays, and the high chemical inertness of polyolefin plastics makes their degradation or chemical recycling challenging. Herein, we demonstrate a chlorine-ion-enabled photocatalytic approach for converting low-density polyethylene (LDPE) under ambient conditions. With an oxygen vacancy-rich bismuth oxychloride (BiOCl-Ov) photocatalyst in a Cl^- anion-containing aqueous solution, chlorine radicals (^•Cl) are generated from the activation of interlayer lattice chloride (Cl_L^-) via a hole-mediated process in BiOCl-Ov, enabling to break the C-H and C-C bonds of LDPE into different carbonic products. Meanwhile, the interlayer Cl_L^- anions are replenished by Cl^- in the electrolyte to maintain sufficient Cl^- species in the catalyst. Under 1-sun illumination intensity and ambient conditions, the BiOCl-Ov photocatalyst exhibited one of the highest LDPE conversion performances without the addition of photosensitizers or sacrificial reagents, including 16.9% LDPE conversion rate and 365 μmol·g_cat^-1 liquid product formation rate, as well as efficient conversion capability for other plastics including polypropylene and polyvinyl chloride.