Atomically engineering the metal-support interaction of single-atom Cu/TiO2 for efficient polyethylene terephthalate plastic photoreforming

Photoreforming with metal single-atom catalysts (SACs) holds promise to transform plastic waste into valuable chemicals. However, optimizing the electronic metal-support interaction (EMSI) to enhance SAC activity and stability remains a significant challenge. Herein, we develop Cu/TiO2 SACs for photoreforming polyethylene terephthalate (PET) plastic. By engineering the local atomic environments around copper (Cu) single atoms (SAs), we achieve a controlled EMSI. The stronger EMSI not only boosts the charge state of Cu SAs, facilitating faster charge transfer and separation, but also induces a narrower band gap to TiO2 support, improving light absorption. Furthermore, the robust EMSI enhances the overall stability of Cu/TiO2 SACs. Over the optimal Cu/TiO2 SACs, PET plastic is upcycled into organic acids (145.4 μmol gcatalyst−1 h−1), alongside H2 generation (193.6 μmol gcatalyst−1 h−1), surpassing bare TiO2 by 25 times and positioning it among the state of the art. The employed atomic engineering strategy for modulating the EMSI offers an efficient approach for designing active and stable SACs.