A high-energy-state biomimetic enzyme of oxygen-deficient MnTiO3 nanodiscs for sensitive electrochemical sensing of the superoxide anion

Abstract

It is of great importance to determine the superoxide anion (O₂˙⁻), a kind of active free radical that plays important roles in catalytic and biological processes. We present here a high-energy-state biomimetic enzyme with extraordinary activity for O₂˙⁻ by inducing surface oxygen defects in MnTiO₃ nanodiscs. Oxygen defects enable surface rich active Mn sites with high oxidation ability, which significantly promote the adsorption and electro-oxidation of O₂˙⁻. The oxygen deficient MnTiO₃ towards O₂˙⁻ exhibits a sensitivity of 126.48 μA μM⁻¹ cm⁻² and a detection limit of 1.54 nM, among the best performance of O₂˙⁻ sensing platforms.