Electrocatalytic Reforming of Polylactic Acid Plastic Hydrolysate over Dynamically Formed γ-NiOOH.

Upcycling plastic waste into valuable commodity chemicals with clean energy is an appealing strategy for mitigating environmental issues. Polylactic acid (PLA), a biodegradable plastic that is produced annually in millions of tons, can be chemically recycled to valuable products instead of being degraded to carbon dioxide. Here, we demonstrate an electrochemical reforming of PLA hydrolysate to acetate and acetonate using nickel phosphide nanosheets on nickel foam (Ni2P/NF) as the catalyst. The Ni2P/NF catalyst was synthesized by electrochemical deposition and phosphide treatment and showed excellent catalytic activity and ∼100% Faraday efficiency for electroreforming PLA to acetate and acetonate in an H-cell. Moreover, a stable performance of more than 90% Faraday efficiency for value-added organics was achieved for a duration of 100 h in a flow cell at a current density of 100 mA cm-2 and a potential below 1.5 V vs. RHE. In situ characterization revealed that the catalyst underwent electrochemical reforming during the reaction to produce γ-phase NiOOH with high electrochemical activity. This work introduces a new and green solution for the treatment of waste PLA, presenting a low-cost and highly efficient strategy for electrically reforming plastics.

Spatial decoupling of bromide-mediated process boosts propylene oxide electrosynthesis.

The electrochemical synthesis of propylene oxide is far from practical application due to the limited performance (including activity, stability, and selectivity). In this work, we spatially decouple the bromide-mediated process to avoid direct contact between the anode and propylene, where bromine is generated at the anode and then transferred into an independent reactor to react with propylene. This strategy effectively prevents the side reactions and eliminates the interference to stability caused by massive alkene input and vigorously stirred electrolytes. As expected, the selectivity for propylene oxide reaches above 99.9% with a remarkable Faradaic efficiency of 91% and stability of 750-h (>30 days). When the electrode area is scaled up to 25 cm2, 262 g of pure propylene oxide is obtained after 50-h continuous electrolysis at 6.25 A. These findings demonstrate that the electrochemical bromohydrin route represents a viable alternative for the manufacture of epoxides.