A perovskite-type KNbO3 nanoneedles based biosensor for direct electrochemistry of hydrogen peroxide

A KNbO3 nanoneedles (KNs) based hydrogen peroxide (H2O2) biosensor was first proposed. Perovskite-type KNs can directly catalyze H2O2. The mechanism can be explained by Molecular Orbital Principles, with the formation of σ-bonding between the eg orbital of surface niobium ions and surface adsorbed oxygen-related intermediate species. Direct electron transfer between the Horseradish peroxidase (HRP) and electrode surface was achieved. Co-catalyst system of both HRP and KNbO3 was introduced to the oxidation of H2O2, thus the as-prepared biosensor exhibited high sensitivity (750 μA mM−1 cm−2) and ultrafast response (1–2 s) to H2O2. Therefore, KNs provide a promising material for enzymes assembly and sensing application.