Heterolytic H₂ activation over platinum supported on oxygen-vacancy-rich CeO₂ (Pt/CeO₂–V_o) for efficient reductive amination of levulinic acid to pyrrolidones under ambient conditions

Abstract

Reductive amination of biomass-derived levulinic acid (LA) to N-substituted-5-methyl-2-pyrrolidone (BMP), versatile nitrogen-containing chemicals, under ambient conditions is highly desirable but challenging due to inefficient H₂ activation. To address this limitation, a platinum (Pt)-based catalyst supported on oxygen-vacancy-rich CeO₂ (Pt/CeO₂-V_o) was developed, comprising uniformly dispersed Pt/PtO₂ heterostructures with adjacent Pt–O–Ce interfacial sites. At these Pt–O–Ce interfaces, electron-deficient Pt and electron-rich O atoms, modulated by neighboring oxygen vacancies, facilitate in situ hydrogen spillover from Pt nanoparticles, generating highly reactive H^𝛿+–O···Pt–H^𝛿– pairs that enable the efficient hydrogenation of the condensation intermediates formed between LA and amine substrates. Therefore, Pt/CeO₂-V_o achieved a high BMP yield of 95.2% with a productivity of 476.0 mol/(mol·h) within 1 h under ambient conditions. Even at a high LA concentration of 11.4% (w), the yield remained above 90%, demonstrating the catalyst’s efficiency under ambient conditions. It also showed excellent recyclability over six consecutive cycles and maintained stable performance for over 80 h in a fixed-bed flow reactor. This work underscores the critical importance of interfacial engineering in optimizing Pt-based catalysts and provides a robust and sustainable strategy for biomass upgrading under mild conditions.

Keywords

Levulinic acid / N-substituted-5-methyl-2-pyrrolidone / Oxygen vacancy / Reductive amination / Ambient condition

References

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