The excellent peroxidase-like activity of uniform CuCo2O4 microspheres with oxygen vacancy for fast sensing of hydrogen peroxide and ascorbic acid

Abstract

High catalytic activity is essential for constructing a rapid and facile colorimetric sensor to determine H₂O₂ and interrelated biomolecules. CuCo₂O₄ microspheres were successfully prepared using a facile hydrothermal and pyrolysis method. The excellent peroxidase-like performance of CuCo₂O₄ microspheres was evaluated by employing a chromogenic substrate, colorless 3,3′,5,5′-tetramethylbenzidine (TMB), which can be catalytically oxidized by H₂O₂ into a blue ox-TMB product within only 1 min. Fluorescence results reveal that the catalytic activity of CuCo₂O₄ is attributed to the increasing amount of ˙OH from the decomposition of H₂O₂ and theoretical simulations by Materials Studio proved that the existence of a large number of oxygen vacancies effectively enhanced the catalytic performance. Based on the high catalytic activity of CuCo₂O₄ microspheres, a rapid colorimetric sensor with high selectivity has been designed for detecting H₂O₂ and ascorbic acid. Under optimal reaction conditions, the linear response ranges of H₂O₂ and AA are 1.00–10.00 mM and 1.00–10.00 μM. The detection limits of H₂O₂ and AA are 132.70 μM and 0.57 μM, respectively.