Efficient upcycling electroplating sludge and waste PET into Ni-MOF nanocrystals for the effective photoreduction of CO2

Upcycling the electroplating sludge (EPS) and PET waste into metal–organic-frameworks (MOFs) is beneficial for both pollution mitigation and sustainable economy. Herein, we report a green synthesis of Ni-MOF nanocrystals by simultaneously using EPS and PET waste as precursors without any precedent. In particular, when EPS was fully utilized, with numerous Fe3+/Cu2+ ions coexisting with Ni2+ ions, the desired Ni-MOFs could still be successfully fabricated. The Ni-MOF nanocatalysts exhibited an excellent activity towards the photoreduction of CO2, giving 9.68 × 103 μmol h−1 g−1 of CO with 96.7% selectivity over H2 evolution. Additionally, the apparent quantum yield at 420 nm is 1.36%, which is superior to that of most catalysts in similar systems. This study clearly suggests that the MOF nanocrystals with excellent photocatalytic performances could be successfully fabricated from solid wastes.