Promoting Active Sites in MOF-Derived Homobimetallic Hollow Nanocages as a High-Performance Multifunctional Nanozyme Catalyst for Biosensing and Organic Pollutant Degradation

Abstract

Nanozymes are one of the ideal alternatives to natural enzymes for various applications. The rational design of nanozymes with improved catalytic activity stimulates increasing attention to address the low activity of current nanozymes. Here, we reported a general strategy to fabricate the Co-based homobimetallic hollow nanocages (HNCs) (C−CoM−HNC, M = Ni, Mn, Cu, and Zn) by ion-assistant solvothermal reaction and subsequent low-temperature calcination from metal−organic frameworks. The C−CoM−HNCs are featured with HNCs composed of interlaced nanosheets with homogeneous bimetallic oxide dispersion. The hierarchical structure and secondary metallic doping endow the C−CoM−HNC highly active sites. In particular, the Cu-doped C−CoCu−HNCs nanostructures exhibit superior performances over the other C−CoM−HNC as both the oxidase mimicking and peroxymonosulfate (PMS) activator. A sensitive bioassay for acetylcholinesterase (AChE) was established based on the excellent oxidase-like activity of C−CoCu−HNC, offering a linear detection range from 0.0001 to 1 mU/mL with an ultralow detection limit of 0.1 mU/L. As the PMS activator, the C−CoCu−HNC was applied for targeted organic pollutant (rhodamine B, RhB) degradation. A highly efficient RhB degradation was realized, along with good adaptability in a wide pH range and good reusability during the eight-cycle run. The results suggest that C−CoCu−HNC holds a practical potential for clinical diagnostics and pollution removal. Further density functional theory calculation reveals that Cu doping leads to a tighter connection and more negative adsorption energy for O 2 / PMS, as well as an upshifted d-band center in the C−CoCu−HNCs nanostructures. These changes facilitated the adsorption of O 2 /PMS on the C−CoCu−HNC surface for dissociation. This work not only offers a promising multifunctional nanozyme catalyst for clinical diagnostics and pollution removal but also gives some clues for the further development of novel nanozymes with high catalytic activities.

Bimetallic metal–organic frameworks and their derivatives

“…Bimetallic MOF-derived porous catalysts have also been developed for a variety of oxidation reactions, such as the oxidation of alcohols, 271,276,277 acetone, olen and toluene, 278 and organic pollutant degradation. 279,280 As an example, Han, Yeung and co-workers prepared a binary metal oxide (CeCuO x ) derived from bimetallic MOFs (CeCuBDC) as the catalyst for the oxidation of organic compounds. 278 In the oxidation of toluene to CO 2 , CeCuO x exhibited high catalytic activity, with a T 50 (temperature required for 50% conversion) and T 90 of 150 and 186 C, respectively (Fig.…”

Self‐assembled CoSe2 Microspheres with Intrinsic Peroxidase Mimicking Activity for Efficient Degradation of Variety of Dyes

“…Among these materials, Co 3 O 4 @Co−Fe oxide DSNCs are employed for dye degradation via peroxymonosulfate (PMS) activation where the very less concentration of dye has been degraded with a comparatively higher dose of catalyst. However, CoSe 2 MS substrate affinity is inferior to Cobalt‐ZIF template‐assisted synthesized bimetallic C−CoCu hollow nanocage [57] reported for PMS activated dye degradation. In another case, CoFe 2 O 4 fails to achieve time economy even with a higher catalyst dose.…”

Mechanistic Insight into Charge and Energy Transfers of Luminescent Metal–Organic Frameworks Based Sensors for Toxic Chemicals

“…[127] Fabricating MOFs with better thermal and chemical stabilities can help provide better binding sites for pesticides. [222,223] A Zn(II)-MOF designed using an (E)-1,2-diphenyl-1,2-bis(4-(pyridin-4-yl)phenyl)ethane linker resulted in sensitive DCN sensing with quenching of the emission (quantum efficiency, 98%). In mechanistic studies, quenching was observed to occur due to binding of the MOF with pesticide DCN through H-bonding interactions (N-H … O) between the analyte amino group and MOF oxygen atom (Figure 5b).…”