Bimetallic nanozyme of Cu–Mn organophyllosilicate with enhanced multi-enzyme mimetic activity for simultaneous degradation of hydroquinone and methylene blue

Abstract

The rational design and construction of high-performance, eco-friendly nanocatalysts for the degradation of organic compounds has been a growing concern in the field of environmental remediation. Herein, instigated by the active centers of laccase and manganese peroxidase, a bimetallic Cu–Mn organophyllosilicate (CAMCP) nanozyme was constructed for the removal of organic dyes. The simultaneous display of multi-enzyme-like activities (laccase-like, oxidase-like, and peroxidase-like) and exceptional catalytic stability under harsh conditions were verified. Specifically, CAMCP exhibits switchable peroxidase/oxidase-like activity due to the non-interfering catalytic activities of Cu and Mn. Moreover, the mechanism indicated that the synergistic effect of Mn and Cu improved the conversion between Cu²⁺ and Cu⁺, facilitating nanozyme activity. Subsequently, CAMCP catalytic decolorization of methylene blue (MB) was performed using hydroquinone (HQ) as the mediator. In contrast to the quinone redox cycling mechanism, hydroquinone acted not only as an electron donor that indirectly accelerated the cycling of Cu²⁺/Cu⁺ but also as a substrate that could be degraded simultaneously during the process. Consequently, the decolorization rate of MB was calculated as 92% within 60 min, whereas HQ was degraded to 70% within 90 min, thereby avoiding environmental pollution. This strategy provides a simplistic and highly efficient route for the rational construction of multi-enzyme-mimetic nanozymes and paves the way for the removal of organic pollutants from aqueous environments.