Porous hierarchical peony-like cobalt-based bimetallic oxides structured by ultrathin nanosheets for highly sensitive electrochemical pesticides detection

Efficient and sensitive electrochemical biosensors are of great significance for on-site measurement and evaluation of pesticides in the environment, and various functional nanomaterials have been designed and developed to achieve this goal. Herein, a kind of three-dimensional holey hierarchical cobalt-based bimetallic oxides randomly assembled by micro-mesoporous ultrathin nanosheets has been exploited. This unique porous hierarchical structure and bimetal composition not only possesses excellent electron pathways and consequent an enhanced electro-conductivity and better catalytic activity , but also exhibits high electroactive surface area and more vacant sites for enzyme immobilization . Along with the highly conductive and biocompatible layered graphdiyne , the 3D porous Co-based bimetallic oxides have been applied to construct an electrochemical AChE biosensor for monitoring dipterex and omethoate (as model OPs pesticides). As a result, the reported biosensor demonstrates superior sensing performance, for example, the wide detection range of 3.88 × 10 −12 –3.88 × 10 −6 M for diptetex and 4.69 × 10 −13 –4.69 × 10 −7 M for omethoate , together with the relative low detection limit of 0.36 pM and 0.033 pM (S/N = 3), respectively. Additionally, the biosensor is feasible in real samples, and the recoveries (94.8–105.1%) are satisfactory. And a possible mechanism has also been proposed. This study offers a new strategy to modulate the property of metal oxides , which make them more attractive in electrochemical sensors .