Nanostructures made of titanium dioxide and/or platinum nanoparticles supported on reduced graphene oxide (RGO) were synthesized by a simple and fast microwave‐assisted route and characterized by X‐ray diffraction (XRD), transmission electron microscopy (TEM), Fourier‐transform infrared (FTIR) and Raman spectroscopies. The composites consist of RGO sheets fully and homogeneously coated with a dense layer of 8 nm TiO2 and/or 2 nm Pt nanoparticles. Screen‐printed flexible sensors based on Pt–TiO2/RGO composites are applied for the amperometric detection of hydrogen peroxide (H2O2). The electrochemical characteristics of Pt/RGO, TiO2/RGO and Pt–TiO2/RGO‐modified screen printed electrodes are investigated and discussed. The developed sensor allows the detection of H2O2, with a linear response from 0 to 20 mM of H2O2 and a sensitivity of 40 μA mM−1 cm−2. The resulting device is also suitable for the analysis of this toxic compound in milk.

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LaxSr1‐xCoyFe1‐yO3‐δ perovskites were investigated as electro‐catalytic materials for H2O2 and glucose electrochemical sensors. La0.6Sr0.4FeO3‐δ and La0.6Sr0.4Co0.2Fe0.8O3‐δ formulations have been synthesized by citrate method and characterized by XRD and SEM. TPR and XPS analyses were performed to evaluate the oxidation states of metal ions and surface composition. The electrochemical performances of H2O2 and glucose sensors fabricated by modifying commercial screen printed carbon electrodes with perovskites, were evaluated by cyclic voltammetry and amperometry in alkaline medium. Results demonstrated that the substitution of Fe with Co ions in the ferrite structure enhance the electrocatalytical activity towards the oxidation of H2O2 and glucose.

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