▎ 摘　　要

In this work, Co3O4 nanoparticles supported on reduced graphene oxide (Co3O4/rGO) were prepared through a simple hydrothermal method. The phosphotriesterase (PTE) mimetic activity of the Co3O4/rGO nanocomposites was investigated for the first time, and the catalytic performance was evaluated by hydrolyzing paraoxon. The synergic effects of Co3O4 and rGO greatly improved the binding capacity of the nano composites with paraoxon and water molecules, and facilitated electron transfer in the hydrolysis process, resulting,in an similar to 5-fold enhancement in the hydrolysis efficiency of Co3O4/rGO nano composites, compared with that of rGO. Co3O4/rGO nano-composites also exhibited excellent reusability and stability than other PTE mimetics. Based on the PTE activity of Co3O4/rGO nanocomposites, a simple and sensitive colorimetric sensor of paraoxon was developed and successfully used to determine the paraoxon in cabbage and river water, demonstrating its potential applicability for food and environmental analyses.