Plastic waste is a global issue threatening the environment and human health. Recycling and upcycling plastic waste are essential for environmental sustainability and transitioning to a circular economy. Recently, researchers in China have made significant progress in this area by developing a Pt/CdS catalyst for transforming polylactic acid (PLA) into green hydrogen and pyruvic acid using photothermal catalysis. This innovative approach combines photochemical and thermochemical reactions, resulting in enhanced catalytic performance. The Pt/CdS catalyst demonstrated exceptional photocatalytic activity in breaking down PLA, with the addition of external heat further improving the process efficiency. Through in situ ESR analysis, the researchers identified the formation of carbon-centered radicals as key intermediates in the conversion of lactic acid, shedding light on the mechanism behind pyruvic acid and hydrogen production. Additionally, DFT calculations highlighted the catalyst's selectivity for certain chemical species, contributing to the overall success of the upcycling process. This study not only emphasizes the importance of catalysis in addressing plastic waste challenges but also underscores the potential of photothermal catalysis for sustainable and efficient conversion of plastic waste into valuable products.