One-Step Synthesis of PtPb Alloy Nanoparticles Via Wet Chemical Method for the Upgraded Recycling of PLA Plastic

Biodegradable plastics such as polylactic acid (PLA) have been extensively applied in numerous fields. Although PLA is degradable in natural environments, its decomposition postdisposal leads to resource wastage. Herein, we first employ enzymatic hydrolysis to degrade PLA. Subsequently, PtPb alloy nanoparticles are synthesized in a single step via a wet chemical method, catalyzing the reformation of the PLA enzymatic hydrolysis products into higher-value chemicals (pyruvic acid). Under conditions of an oxygen flow rate of 60 mL/min, a reaction temperature of 90 °C, and a reaction duration of 60 min, the conversion rate of lactic acid catalytic oxidative dehydrogenation to pyruvic acid reaches an impressive 96.86%, with a selectivity of 95.69%. Moreover, this catalyst exhibits satisfactory stability. Experimental and density functional theory (DFT) calculations are combined to ascertain the active state changes of PtPb and the reaction pathways for the catalytic oxidative dehydrogenation of lactic acid to pyruvic acid, as well as the free energy changes of different catalysts in this transformation. In this work, we employ a simple synthetic strategy to specifically investigate the impact of PtPb alloy nanoparticles under various conditions on the catalytic oxidative dehydrogenation of lactic acid to pyruvic acid, offering a new research avenue for the waste treatment and resource utilization of biodegradable plastics in the future.