Nanozymes are next-generation of nanomaterials with enzyme-like activities. In particular, nanozymes with peroxidase (POD)-like activity have been utilized in various fields, including antibacterial, detection, degradation, etc. However, their extensive applications were limited by their low catalytic activity currently. Herein, we have presented a composite nanozyme based on attapulgite (ATP) (Fe-ATP-MoS₂, (FAM)), which exhibited enhanced POD-like activity (185.33 U·mg⁻¹), 4.25 times higher than that of Fe-MoS₂ (FM) (43.63 U·mg⁻¹). The density functional theory (DFT) calculations indicated that the addition of ATP increased the electron density of metal centers (Mo and Fe). More importantly, Michaelis-Menten kinetics revealed that the introduction of ATP significantly enhanced the binding affinities of substrates through the pores of ATP, forming a highly concentrated substrate microenvironment and thus promoting its POD-like activity. Additionally, from molecular size and kinetic analysis, we proposed that the changes in substrate size before and after oxidation also significantly affected its Michaelis-constant (Km) value. Furthermore, we utilized FAM in the applications of highly effective antibacterial application and sensitive detection of glutathione (GSH). In conclusion, this work provides a novel approach for designing a highly efficient nanozyme based on natural mineral composites.

Light-drive hydrogen production using titanium-based perovskite is one sustainable way to reduce current reliance on fossil fuels, but its wide applications are still limited by high electron-hole recombination and sluggish surface reaction. Thus, the developments for low-cost and highly efficient co-catalysts remain urgent. Inspired by natural [NiFe]-hydrogenase active center structure, a hydrogenase-mimic, NiCo₂S₄ nanozyme was synthesized, and subsequently decorated onto the CaTiO₃ to catalyze the hydrogen evolution reaction (HER). Among the following test, CaTiO₃ with a 15% loading of NiCo₂S₄ nanozyme exhibited the highest HER rate of 307.76 μmol·g^-1·h^-1, which is 60 times higher than that of the CaTiO₃ alone. The results revealed that NiCo₂S₄ not only significantly increased the charge separation efficiency of the photogenerated carriers, but also substantively lowered the HER activation energy. Mechanism studies show that NiCo₂S₄ readily splits H₂O by forming the Ni(OH)-Co intermediate and only Ni in the bimetallic center alters the oxidation state during the HER process in a manner analogous to the [NiFe]-hydrogenase. In contrast to the often-expensive synthetic catalysts that rely on rare elements such as ruthenium or platinum, this study shows a promising way to develop the nature-inspired cocatalysts to enhance the photocatalysts’ HER performance.

Rational design of metallic active sites and its microenvironment is critical for constructing superoxide dismutase (SOD) nanozymes. Here, we reported a novel SOD nanozyme design, with employing graphene oxide (GO) as the framework, and δ-MnO₂ as the active sites, to mimic the natural Mn-SOD. This MnO₂@GO nanozyme exhibited multiscale laminated structures with honeycomb-like morphology, providing highly specific surface area for ·O₂⁻ adsorption and confined spaces for subsequent catalytic reactions. Thus, the nanozyme achieved superlative SOD-like catalytic performance with inhibition rate of 95.5%, which is 222.6% and 1605.4% amplification over GO and MnO₂ nanoparticles, respectively. Additionally, such unique hierarchical structural design endows MnO₂@GO with catalytic specificity, which was not present in the individual component (GO or MnO₂). This multiscale structural design provides new strategies for developing highly active and specific SOD nanozymes.