In Situ Cu-N Sites: Weak Interactions Drive Strong Catalysis by Mimicking Cu-His Metallocofactor

Structural bionics have been widely adopted in nanozyme design, yet catalytic activity remains constrained within intrinsic active centers due to their rigid frameworks. Here, by simply introducing imidazole (ImH) into the reaction system, we unlock in situ generated active sites upon the inherent centers, achieving a 110-fold enhancement in the maximum reaction rate of 2,4-chlorophenol oxidation catalyzed by CuO nanozymes. Mechanistic investigations reveal that Cu─N sites dynamically formed via reversible coordination of ImH on the CuO surface act as superior reactive sites, replacing the static Cu─O centers. Crucially, synergistic electronic modulation promotes Cu redox reversibility in ImH-coordinated CuO, evidenced by a more positive reduction potential and reduced potential difference (ΔE = 93 mV), thus accelerating electron transfer during catalytic oxidation. Moreover, similar to the dynamic coordination of histidine residues during enzymatic catalysis, reversible shifts in wavenumber and variations in peak intensity are observed in the in situ FTIR spectra when comparing the states of ImH adsorption and co-catalytic oxidation, highlighting the substrate-responsive adaptability of the Cu─N sites. This co-factor assisted nanozyme system unveils a new class of catalytic sites accessed through relatively weak molecular interactions and establishes a foundation for adaptive engineering of enzyme-mimicking coordination environment.