Synergistic catalysis at Cu0–Cu+interfaces in a MOF-derived Cu@Cu₂O/NC heterostructure for enhanced 4-nitrophenol conversion

Achieving high activity, superior selectivity, and durable performance remains challenging for pristine MOFs in heterogeneous hydrogenation catalysis. Herein, nitrogen-doped carbon-wrapped Cu@Cu₂O/NC heterogeneous catalysts enriched with Cu0–Cu+ interfacial sites were readily derived by calcining Cu-MOF under an air atmosphere. Comprehensive characterization was conducted to examine synthesis-induced variations in bulk crystallinity, surface chemistry, and catalytic activity for Cu-MOF-250, Cu-MOF-350, and Cu-MOF-450. Compared to its counterparts, the Cu-MOF-350 catalyst exhibited optimal performance in the preferential hydrogenation of noxious 4-nitrophenol (4-NP) to valued 4-aminophenol (4-AP), maintaining high activity for up to ten consecutive rounds. The enhanced catalytic hydrogenation efficiency of the Cu-MOF-350 catalyst is ascribed to its distinctive nanostructural features, which originate from the synergistic interplay between Cu and Cu₂O species. In addition, the improved uniform distribution of Cu@Cu₂O nanoparticles generates higher concentration of interfacial exposed reactive Cu0/Cu+ sites on the Cu-MOF-350 surface, which are considered crucial for the promoted hydrogenation of 4-NP.