Single-Atom Nanozyme Based on Mn-Center with Enhanced Peroxidase-like Activity for Organic Dye Degradation

Abstract

Compared with natural enzymes, nanozymes have advantages such as high stability, low cost, and a broad application prospect. However, due to the low catalytic activity of conventional nanozymes, synthesizing nanozymes with excellent enzyme-like activity will be long-term work. Herein, we synthesized single-atom nanozymes centered on Mn with N, P, and S doped (Mn-SAzyme) with enhanced peroxidase-like (POD-like) activity. We found that the presence of the Mn metal center significantly increased the POD-like activity of the nanozyme, exhibiting catalytic properties consistent with Michaelis–Menten kinetics. The POD-like activity was measured to be 17.48 U/mg, which was higher than that of the sample without the metal center. Using methylene blue (MB) as the organic dye model, the degradation efficiency of Mn-SAzyme could reach 90.1% within 300 min at pH 6.5, within the H2O2 concentration of 0.1 M and 25 mg/L of nanozyme dosage. Free radical quenching experiments and electron paramagnetic resonance tests showed that •O2 – and •OH were the key to degrading organic dyes. This work aims to explore more methods for synthesizing highly active nanozymes and successfully applying the synthesized nanozymes to the degradation of organic dyes.

Nanozymes: powerful catalytic materials for environmental pollutant detection and degradation

“…On the one hand, many materials with peroxidase-like catalytic features have been utilized to fabricate Fenton-like systems to degrade these dyes. 44,[198][199][200][201][202][203][204][205][206][207][208][209][210][211][212][213][214][215] For example, Lin's group presented a strategy to construct graphene-gold nanoparticles (graphene/Au-NPs) through a one-step hydrothermal procedure, which acted as an effective scavenger for dyes with the synergetic impact of degradation and adsorption. 200 When different contents of the graphene/ Au-NPs material and H 2 O 2 (300 mM) were introduced to 10 μg mL −1 dye solutions, the remained dye levels were assessed by recording the supernatant's absorbance after removing graphene/Au-NPs.…”

Advanced nanozymes possess peroxidase-like catalytic activities in biomedical and antibacterial fields: review and progress

“…However, compared to natural enzymes, which are expensive and difficult to store, these artificial enzymes offer significant advantages in terms of cost and storage, positioning them as potential substitutes for natural enzymes across various applications. 16…”

“…However, compared to natural enzymes, which are expensive and difficult to store, these artificial enzymes offer significant advantages in terms of cost and storage, positioning them as potential substitutes for natural enzymes across various applications. 16 Although a wide array of enzyme-like activities can be mimicked by nanozymes, only a few activities possess direct bactericidal capabilities, including OXD, halo peroxidase (HPO), and POD activities. Other enzyme-mimicking activities such as CAT and SOD activities are utilized to eliminate ROS post-antibacterial action.…”

Perspectives for the Role of Single-Atom Nanozymes in Assisting Food Safety Inspection and Food Nutrition Evaluation

“…The constructed method based SAzymes can degrade 300% of MB in 90 min with a very small amount of SAzymes. 77 Food Contaminant. Detection of Toxins.…”

“…Feng et al synthesized a Mn-centered, N, P, S metal-doped SAzyme with high POD-like activity used in a wide pH range. The constructed method based SAzymes can degrade 300% of MB in 90 min with a very small amount of SAzymes …”