Ultrafast light-driven carbonization of waste tires into functional carbon supports for high-performance fuel cells

The electricity-free conversion of polymer waste into high-value functional materials represents an important step toward sustainable and circular manufacturing. Herein, we demonstrate a light-driven upcycling platform that directly transforms vulcanized waste tires into electrocatalyst supports for proton exchange membrane fuel cells (PEMFCs). In this process, waste tires form uniform composites with effective light absorbers such as MoS₂ nanosheets, enabling near-infrared (NIR) light or natural sunlight to be converted into localized high-temperature thermal fields. By investigating the fundamental correlation between composite design, microstructure, and carbonization efficiency, we show that waste tires are turned into effective Pt catalyst supports via NIR- and sunlight-driven carbonization. The resulting PEMFCs deliver a maximum power density of 982 mW cm^-2 (NIR) and 1048 mW cm^-2 (natural sunlight), respectively, under H₂/O₂ operation, which are comparable to that of a benchmark Pt/C device (1024 mW cm^-2). These results demonstrate that the light-driven carbonization enables the production of carbon supports with sufficient conductivity, Pt accessibility, and catalyst-layer compatibility for fuel-cell operation. Additionally, sunlight-based photothermal carbonization is accomplished in less than 1 min under ambient conditions, highlighting its potential as an alternative to conventional, energy-intensive, and time-consuming furnace-based carbonization. Ultimately, this light-driven upcycling strategy offers an efficient, self-sustained route for converting polymer waste into functional electrochemical materials.