Synthesis and intrinsic enzyme-like activity of β-MnOOH nanoplates

•Single phase β-MnOOH was fabricated via a facial hydrothermal and air oxidation route.•It is first found to have peroxidase-like activity.•It has two advantages, including high efficiency and long-term stability.•It has great potential use of bio/chemical detection.

Single phase β-MnOOH with high crystallinity was successfully synthesized by a method combining controlled hydrothermal synthesis and subsequently air oxidation. The results of X-ray diffraction, scanning electron microscopy, transmission electron microscopy showed that the as-prepared β-MnOOH had a thin hexagonal layered structure, uniform particle size distribution, and good dispersion. The presence of hydrazine and suitable hydrothermal temperature (140 °C) are of the two key factors to synthesize pure phase β-MnOOH. The synthesized β-MnOOH nanoplates could catalyze the oxidation reaction of peroxidase substrate 3,3′,5,5′-tetramethylbenzidine in the absence of H2O2 to produce a blue color change, indicating an intrinsic enzyme-like activity. Furthermore, as an inorganic enzyme mimic, β-MnOOH also showed high stability, which facilitates its potential applications as enzyme mimics in biosensor, biotechnology, and biomedicine.

Graphical abstractβ-MnOOH nanoplates with good crystallinity, uniform particle distribution, and good dispersion can catalyze the oxidation reaction of peroxidase substrate TMB in the absence of H2O2 to produce a blue color change.Figure optionsDownload full-size imageDownload as PowerPoint slide