Mesoporous medium-entropy nanozyme with enhanced peroxidase-like activity: design, mechanism, and application as a sensor for ultrasensitive detection of trace thiophanate methyl.

BACKGROUND

Medium-entropy alloy nanozyme (MEAzyme) with mesoporous framework, unique regular morphology, and excellent enzyme-like catalytic performance have shown great application potential. However, synthesizing MEAzymes that balance well-defined mesoporous structures and preserve unique regular morphology remains a challenge. Herein, in this study, a universal solvent-mediated polymerization-induced self-assembly (PISA) strategy was successfully used to design a mesoporous FeCuMn-MEAzyme with a regular and uniform spherical morphology.

RESULTS

The mesoporous FeCuMn-MEAzyme exhibits superior POD-like catalytic performance, which can be attributed to the "cocktail effect" of multimetallic active centers, high specific surface area (up to 236.40 m2/g), and large pore size (2.85∼13.09 nm). Interestingly, the POD-like activity of this nanozyme can be immediately and strongly by the thiophanate-methyl (TM). Accordingly, a FeCuMn-MEAzyme colorimetric sensor was developed for the ultrasensitive (LOD = 0.83 ng/mL) and selective detection of TM with showing an outstanding linear relationship over the range of 0.0010 μg/mL to 40.00 μg/mL. In addition, a rapid smartphone-integrated FeCuMn-MEAzyme colorimetric sensing platform was also constructed, which achieved a low LOD (0.78 ng/mL) for TM detection.

SIGNIFICANT: The developed FeCuMn-MEAzyme-based method was successfully applied to detect TM in environmental samples. This work provides a universal synthesis strategy for mesoporous MEAzyme with regular morphology and enhanced POD-like activity, demonstrating great potential in analytical and sensor applications.