Ambient solar thermal catalysis for polyolefin upcycling using copper encapsulated in silicon nanosheets and chloroaluminate ionic liquid

The accumulation of plastic waste has become a global issue. Socially and industrially viable, sustainable technical solutions are therefore required. Here we report a solar thermal catalytic system for polyolefins upcycling using copper nanoparticles encapsulated by stacked two-dimensional silicon. In a chloroaluminate ionic liquid solvent, unlike conventional thermal techniques, the upcycling can proceed under a mild temperature (55 °C) created photothermally under 4 sun irradiation. The polyethylene can be completely transformed into distinct and separable fractions of alkanes (C 3 –C 7 ) and cyclic hydrocarbons (C 8 –C 26 ) within hours, with a total yield of 91%. Mechanistic studies show a pathway involved two β-scissions of C–C bonds and a rapid cyclization. The approach offers versatility in the upcycling of various real-world polyolefin waste and features excellent feasibility in outdoor practices. The analyses of a conceptual upcycling facility using this technology showcase its appeal in both economic and eco-friendliness.