Kinetics and mechanism of copper sulfide/graphdiyne nanozyme with enhanced peroxidase-like activity for efficient dye degradation

In this work, a hollow cubic CuS was synthesized via the etching of Cu2O, followed by the in-situ growth of graphdiyne (GDY) on its surface to yield a CuS/GDY composite nanozyme. The synergistic interaction between CuS and GDY endowed the nanozyme with pronounced peroxidase-like activity, facilitating the oxidation of substrates such as TMB, OPD, and ABTS in the presence of H2O2. Kinetic studies indicated a higher affinity of CuS/GDY for TMB compared to horseradish peroxidase (HRP), with a lower Km value for TMB. Radical scavenging experiments identified hydroxyl radicals (<middle dot>OH) and singlet oxygen (1O2) as the primary reactive oxygen species (ROS) responsible for the catalytic oxidation. CuS/GDY also exhibited exceptional catalytic degradation of Rhodamine B (Rh B), achieving a degradation rate of 90.5% within 40 min. Moreover, the composite exhibited excellent stability and recyclability in complex aqueous environments, the catalyst's reusability was confirmed with over 70% efficiency after multiple cycles, demonstrating its potential as a novel, continuous approach for efficient wastewater treatment and environmental remediation.