A novel hierarchical flower-like ZnO@CuCo2O4 core–shell nanorod composite for non-enzymatic glucose sensing

Abstract

Developing a highly sensitive enzyme-free glucose sensor is critical, given the significant health risks posed by diabetes. In this study, a ZnO@CuCo₂O₄ composite with a novel flower-like heterostructure assembled by nanorods is prepared utilizing straightforward hydrothermal and calcination processes. The core–shell ZnO@CuCo₂O₄ featuring ZnO as the core and CuCo₂O₄ as the shell can improve the agglomeration phenomenon of CuCo₂O₄, expose more active sites, and promote efficient electron transfer. A ZnO@CuCo₂O₄ based non-enzyme glucose sensor is constructed and tested for the first time, which exhibits good sensing performance, a low limit of detection of 0.82 μM, with broad linear ranges of 10–1725 μM and 1725–9225 μM, yielding sensitivities of 898 and 524 μA mM⁻¹ cm⁻², respectively, and a rapid response time of only 2 seconds. Furthermore, it shows excellent selectivity, long-term stability (retaining 92.42% of its initial response current after 20 days), and good reproducibility, including in real saliva samples. The superior sensing performance of the ZnO@CuCo₂O₄ sensor can be attributed to the synergistic effects of the core–shell n–p heterostructure, the integration of amorphous and crystalline dual phases, and the flower-like structure, which collectively optimize electron transfer and electrocatalytic activity. This work offers a cost-effective and innovative strategy for advancing enzyme-free glucose sensing technologies.