Hierarchical Cu3V2O8/Cu6Mo5O18/MXene nanostructures by ultrathin nanosheets for highly sensitive electrochemical detection of organophosphorus pesticides

Transition-metal oxides (TMOs) with hierarchical nanostructures derived from metal organic frameworks (MOFs) were widely applied in electrochemical investigation. In this paper, a rational synthesis strategy of TMOs with specific nanostructures and multiple components was reported. Three-dimensional (3D) CuMoV layered metal hydroxides (CuMoV LDHs) architecture was prepared by mild and facile wet-chemistry process to reshape Cu-MOF surface and realize the self-templated conversion. After thermal annealing, hierarchical CuMoV LDHs were transformed to polynary Cu3V2O8/Cu6Mo5O18 (CMVO) compounds. Based on the electrostatic attraction, CMVO/MXene (CMVON) compounds were assembled by combining the CMVO and few-layer Nb2CTx MXene (f-Nb2C) nanosheets and employed as modified materials on the electrode surface. Benefiting from the superior electronic conductivity, large surface area and shortened ion diffusion pathway, the CMVON hybrids demonstrated excellent electrochemical sensing properties. Upon optimum conditions, the constructed CMVON based AChE biosensor manifested markedly analytical performance with the low limit of detection (LOD) and wide linear ranges for parathion-methyl, malathion, and fenitrothion detection.