Peroxidase-Like Layered Double Hydroxide Nanoflakes for Electrocatalytic Reduction of H₂O₂

Peroxidase-like layered double hydroxide (LDH) nanoflakes were synthesized directly and facilely by a one-pot chemical method, hydrothermal treatment. The as-prepared LDHs were characterized by transmission electron microscopy, scanning electron microscopy, X-ray diffraction, Fourier transform IR, and cyclic voltammetry. The functionalized LDHs immobilized on the glassy carbon electrode exhibited a well-defined pair of redox peaks, excellent electrocatalytic activity toward the reduction of hydrogen peroxide without inhibition of dissolved oxygen and a higher affinity for H2O2, just like the peroxidase. The low apparent Michaelis-Menten constant was only 242 mu M. ne electrochemical response to H2O2 shows a linear range of 12-254 mu M with the calculated detection limit of 2.3 mu M at a signal-to-noise ratio of 3. Furthermore, compared with most metal hexacyanoferrates, the peroxidase-like LDHs are very stable in neutral and alkaline solution. The electrochemical and electrocatalytic behavior of the functionalized LDHs indicate that they may be useful to explore man-made mimics of enzyme in electrochemical biosensors.