▎ 摘　　要

Real-time monitoring of hydrogen peroxide (H2O2) released from living tumor cells is still a huge challenge. Herein, reduced graphene oxide supported dumbbell-shaped CuCo2O4 (CuCo2O4/rGO) was prepared via a facile hydrothermal procedure and an annealing treatment. The CuCo2O4/rGO possess intrinsic peroxidase-like activity, while the 3D dumbbell-shaped sructure consisting of 2D nanosheet layers with large surface area and high conductivity can efficiently enhance electrocatalytic performance of the composites. The CuCo2O4/rGO modified glassy carbon electrode (CuCo2O4/rGO/GCE) exhibited good electrocatalytic performances toward H2O2 with a sensitivity about 320.3 mu A mM(-1) cm(-2) and a low detection limit of 80 nM in a linear range of 30-5010 mu M. Furthermore, the CuCo2O4/rGO/GCE electrochemical sensor was successfully used for real-time detection of H2O2 released from living cells, indicating the potential application of CuCo2O4/rGO in monitoring the critical pathological process in living cells.