Co3O4@CeO2 hybrid flower-like microspheres: a strong synergistic peroxidase-mimicking artificial enzyme with high sensitivity for glucose detection.

In recent years, the development of artificial nanostructured enzymes has received enormous interest in nanobiotechnology due to their advantages over natural enzymes. In the present work, different amounts (5, 10, and 20 wt%) of Co3O4 nanoparticle decorated CeO2 hybrid flower-like microspheres (Co3O4@CeO2) have been investigated for peroxidase-like activity and it was found that 10 wt% of Co3O4@CeO2 exhibited excellent peroxidase-like activity for the catalytic oxidation of the 3,3',5,5'-tetramethylbenzidine (TMB) substrate in the presence of H2O2. The formation of more Ce3+ ions associated with the oxygen vacancies and a strong synergistic interaction between CeO2 and Co3O4 may be responsible for the enhanced peroxidase-like activity. Based on their peroxidase activity, Co3O4@CeO2 hybrid microspheres were used for the colourimetric detection of glucose. It was found that Co3O4@CeO2 hybrid microspheres showed a substantial enhancement in the detection selectivity. The limit of detection (LOD) was also improved with a limit as low as 1.9 μM. Thus, we believe that Co3O4@CeO2 hybrid flower-like microspheres with high peroxidase-like activity can be exploited for biosensing applications.