Photocatalytic Conversion of Polyester-Derived Alcohol into Value-Added Chemicals by Engineering Atomically Dispersed Pd Catalyst.

Abstract

Photoreforming presents a promising strategy for upcycling waste polyester-derived alcohol into valuable chemicals. However, it remains a great challenge due to its low performance and unsatisfactory selectivity toward high-value C2 products. Here, we report the highly efficient and selective conversion of ethylene glycol (EG, a monomer of polyethylene terephthalate (PET)) to glycolaldehyde using atomically dispersed Pd species supported on TiO2 catalyst. A glycolaldehyde production rate of 5072 μmol gcat-1 h-1 with a selectivity of 90.0% and long-term durability can be achieved. Experimental and theoretical results show that Pd single atoms can enhance the photocatalytic activity by enriching the photogenerated holes, which are the dominant species for the selective oxidation of EG to glycolaldehyde. More importantly, the adsorption of EG molecules on the catalysts is significantly promoted, which is subsequently transformed into RO• radicals, a crucial intermediate in producing glycolaldehyde. Additionally, Pd single atoms on TiO2 enable the reduction of the glycolaldehyde desorption barrier, thereby facilitating high selectivity and inhibiting further oxidation to C1 products. This work provides new insights into the photocatalytic conversion of polyester wastes by atomic engineering.