Direct electron transfer of hemoglobin intercalated in exfoliated Ni–Al–CO3 layered double hydroxide and its electrocatalysis towards hydrogen peroxide

Abstract

In this study, hemoglobin (Hb) was entrapped into the exfoliated Ni–Al–CO₃ layered double hydroxides (LDH). UV-vis spectra analysis displayed that no significant denaturation occurred to the protein. Electrochemical results showed that exfoliation of LDH enhanced the direct electron transfer between protein molecules and electrode, and the entrapped protein showed high bioactivity in a wide range of pH values. A pair of well-defined redox peaks was observed at −0.39 and −0.33 V on the glassy carbon electrode (GCE) modified with the Hb–LDH composite. The electrode reactions showed a surface-controlled process with single electron transfer at the scan rate from 100 to 400 mV s⁻¹. The sensor constructed displayed an excellent response to the reduction of hydrogen peroxide (H₂O₂) with a wide linear range, low detection limit and good stability. The modified electrode can also be used for the reduction of oxygen.