Alanine Production by Chemical Upcycling of Polylactic Acid Waste Over Fe-Doped Ru/CeO₂

Biodegradable polyesters, such as polylactic acid (PLA), is one of the most promising plastics with great potential to contribute to enabling a sustainable global circular economy. However, the efficient chemical upcycling of PLA plastic waste into high-value chemicals remains a grand challenge. Herein, a series of Ru/CeFeO_x catalysts with varying Ru loadings were developed for the catalytic amination of PLA plastic waste to alanine in the presence of ammonia. The as-prepared catalysts exhibited exceptional catalytic activity, high selectivity, and excellent recyclability, achieving an alanine yield of 70.5 % at 180 °C for 18 h, significantly surpassing previous reports. The outstanding catalytic performance can be primarily attributed to the presence of Fe species in Ru/CeFeO_x, which generated more oxygen vacancies, provided abundant base sites, and enhanced reducibility, therefore accelerating the reaction rate and enhancing catalytic efficiency. This study presents an alternative strategy for the sustainable chemical upcycling of PLA plastic waste into alanine and the realization of a circular economy.