Elevated electrochemical activity of double perovskites PrBaCo2-xNixO6-δ towards hydrogen peroxide oxidation

[Display omitted] •Enzyme-free sensors for H2O2 based on layered oxides are firstly examined.•Layered structure is shown to benefit an electrochemical activity of the electrodes.•A sharp increase of electrode’s sensitivity with nickel doping is observed.•Different mechanisms of peroxide oxidation on the surface are considered. The complex oxides with the ordered perovskite-like structure were carefully examined as enzyme-free electrochemical sensors with a stable and sensitive response to the hydrogen peroxide for the first time. The ordered perovskites PrBaCo2O6-δ (PBC) and PrBaCo1.9Ni0.1O6-δ (PBCN) were synthesized by glycine-nitrate combustion method and characterized by means of XRD, SEM and XPS. Thermogravimetry and iodometric titration were implemented to evaluate the average oxidation states of B-site transition metals and the oxygen non-stoichiometry. Electrochemical properties of double perovskites towards H2O2 were comprehensively studied by a combination of cyclic voltammetry and chronoamperometry in an alkaline media. The PBCN-based electrode is shown to possess a considerable sensitivity (1078.31 μA cm−2 mM−1) with a suitable detection limit and linear range. In addition, the influence of more oxidized forms of B-site cations, oxygen vacancies, and diffusion coefficient values at peroxide electrocatalytic properties were discussed.