Glycine photosynthesis via C−N coupling of waste plastic and nitrate over diatomic Pd−B catalyst

Photocatalytic C−N coupling offers a promising approach for the sustainable production of amino acids, but the uncontrolled coupling pathway of reaction intermediates limits yield and selectivity. This paper describes a Pd−B diatomic catalyst that can selectively catalyze the photosynthesis of glycine via C−N coupling reaction between waste poly(ethylene terephthalate)-derived ethylene glycol and nitrate, achieving a glycine yield of 2.9 mmol gcat−1 h−1 with a selectivity of 92%. Mechanistic investigations reveal that ethylene glycol is photo-oxidized to glycolaldehyde at the hole-rich B site, while nitrate is photo-reduced to NH4+/NH3 at the electron-rich Pd site. Subsequently, glycolaldehyde undergoes C−N coupling with NH4+/NH3, and further photo-oxidized to form glycine. The Pd−B diatomic site more effectively stabilizes the glycolaldehyde intermediate, resulting in a more favorable C−N coupling pathway than metal oxide and enhancing glycine selectivity. Thus, we show a catalytic system for selective glycine photosynthesis by precisely regulating the reaction pathways of key intermediates. This work describes a Pd−B diatomic catalyst that can selectively catalyze the photosynthesis of glycine via C−N coupling reaction between PET-derived ethylene glycol and nitrate, achieving a yield of 2.9 mmol gcat−1 h−1 and selectivity of 92%.