Photocatalytic Upgrading of Polylactic Acid Waste into Alanine under Mild Conditions

Abstract Polylactic acid (PLA) has attracted increasing interest as a sustainable plastic because it can be degraded into CO 2 and H 2 O in nature. However, this process is sluggish, and even worse, it is a CO 2 ‐emitting and carbon resource waste process. Therefore, it is highly urgent to develop a novel strategy for recycling post‐consumer PLA to achieve a circular plastic economy. Herein, we report a one‐pot photoreforming route for the efficient and selective amination of PLA waste into value‐added alanine using CoP/CdS catalysts under mild conditions. Results show the alanine production rate can reach up to 2.4 mmol g cat −1 h −1 , with a high selectivity (>75 %) and excellent stability. Time‐resolved transient absorption spectra (TAS) reveal that CoP can rapidly extract photogenerated electrons from CdS to accelerate proton reduction, favoring hole‐dominated PLA oxidation to coproduce alanine. This study offers an appealing way for upcycling PLA waste and creates new opportunities for green synthesis of amino acids.