Isolated Ni atoms enable alkali-free photoreforming of waste polylactic acid plastic.

Hu, Miao; Feng, Chengyang; Alharbi, Jumanah; Zuo, Shouwei; Ladelta, Viko; Alshehry, Ghassan S; Ruwaili, Khalid; Al Qahtani, Hassan S et al. · Nat Commun · 2025

basic_science · Level V

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Abstract

Although polylactic acid is a promising biodegradable plastic, its slow degradation under natural conditions, microplastic formation, and CO<sub>2</sub> emissions during decomposition undermine its sustainability. Photoreforming offers a promising strategy for polylactic acid conversion; however, current methods suffer from sluggish kinetics and low selectivity. Here, we design a Ni single-atom catalyst anchored on CdS (Ni/CdS) to enable alkali-free photoreforming of real polylactic acid plastic waste under mild conditions. Ni single atom sites facilitate sequential cleavage of α-OH and C<sub>α</sub>-H bonds, enabling efficient H<sub>2</sub> evolution and significantly improving the yield and selectivity of polylactic acid conversion to H<sub>2</sub> and pyruvic acid, achieving an apparent quantum efficiency of 46%. Furthermore, we successfully scaled up the synthesis of Ni/CdS and implemented a square-meter-scale reaction system, demonstrating stable outdoor photoreforming of real polylactic acid plastic waste under sunlight. This work paves a promising pathway for solar-driven upcycling of polylactic acid plastic waste.