LAUSR

Polymorphs of Manganese di oxide (MnO2) such as alpha (α), beta (β), gamma (γ), epsilon (ϵ), and MnOOH type materials were prepared via hydrothermal approach under different conditions. The samples were characterized by XRD, FESEM, FT-IR, Raman and BET analysis. Cyclic voltammetry (CV) analysis confirm that α - MnO2 shows better electro-catalytic ability. Amperometry sensing of hydrogen peroxide (H2O2) was carried out by varying applied potential value with the polymorphs of MnO2. Compared with the other phases of MnO2, α - MnO2 shows high linear range up to 20μM. The calculated sensitivity value for H2O2 sensing of different phases is in the order of α - MnO2, β - MnO2, ϵ - MnO2, γ - MnO2, MnOOH and found to be 0.094 mA μM−1 cm−2 > 0.072 mA μM−1 cm−2 > 0.07 mA μM−1 cm−2 > 0.03 mA μM−1 cm−2 > 0.01 mA μM−1 cm−2 respectively. All the characterization results reveal that crystalline phase plays a vital role in electrochemical behavior rather than crystalline size, morphology, surface charge, surface area.