Mg and Ni nano-hydrotalcites modified with gold nanoparticles as platform of enzymatic electrochemical sensors for H2O2 detection

The immobilization of Horseradish Peroxidase enzyme over Magnesium (Mg-nHT) and Nickel (Ni-nHT) nano Hydrotalcite clays were synthesized by the co-precipitation method, and later modified with gold nanoparticles through in-situ synthesis and delamination-restructuration, is reported. The synthesized materials were characterized by Fourier-Transform Infrared Spectroscopy, X-ray diffraction, Scanning Electronic Microscopy, Flame Atomic Absorption Spectroscopy and Cyclic Voltammetry. Results show that the size of the synthetized materials is 26 nm for the gold nanoparticles, and 38.92 nm and 8.44 nm for Mg-AlnHT and Ni-AlnHT, respectively. The clays were used to modify the surface of graphite electrodes (GE); the inclusion of Au nanoparticles in the Hydrotalcites structure improved the enzyme-electrode electric communication. Figures of merit for detection of H2O2 by Differential-Pulse Voltammetry at HRP/Mg-AlnHT/GE, HRP/Ni-AlnHT/GE, HRP-AuNps/Mg-AlnHT/GE and HRP-AuNps/Ni-AlnHT/GE modified electrodes were determined, and respective detection limits of 0.012 μmolL−1, 0.014 μmolL−1, 0.009 μmolL−1, and 0.010 μmolL− 1 were obtained.