Hydrogen bond regulation to enhance catalytic C–C bond cleavage of polylactic acid wastes in H2O to produce H2

Abstract

Polylactic acid (PLA) as a biodegradable plastic currently has the highest production among the global bio-based plastics. In comparison to the natural degradation of PLA with a substantial period of time, the development of a novel transformation process for the upcycling of PLA plastic into green H₂ and CO₂ using H₂O is of great significance. Herein, a hydrogen bond regulation strategy with a Ni–Fe catalyst is proposed to achieve the direct transformation of PLA plastic wastes in H₂O into CO₂ and H₂ at 310 °C. The fabricated Ni–Fe catalyst enables the cleavage of the intramolecular hydrogen bond in PLA-derived oxygenates to convert various PLA plastic wastes in H₂O, and H₂ production reaches up to 62.6 mmol g_plastic⁻¹ accompanied by a H₂ selectivity of 93.5%. Further investigation of the reaction pathway reveals that, compared to the Ni catalyst, the incorporation of Fe into Ni greatly enhances the catalytic cleavage of intramolecular hydrogen bonds, which further accelerates C–C bond cleavage. And it displays tremendous hydrogen production capability over ten cycles. This approach provides an innovative solution for upgrading PLA wastes into sustainable hydrogen and contributes to a low-carbon future.