Ni-Co-LDH and Zn-Co Prussian blue analogue derived hierarchical NiCo2O4@ZnO/ZnCo2O4 microspheres with enhanced electrochemical sensing performance towards pentachloronitrobenzene

In this work, we developed a hierarchical structure and multi-component synergistic metal oxide hybrid material, and explored its practical application in monitoring pentachloronitrobenzene (PCNB). We used the ZnO/ ZnCo2O4, obtained by calcining Zn-Co Prussian blue analogue (PBA), as the substrate and integrated Ni-Co layered double hydroxide (LDH) on its surface and calcined to obtain hierarchical NiCo2O4@ZnO/ZnCo2O4 microspheres (MSs). Due to the p-n heterojunction characteristics of p-type semiconductor NiCo2O4 and ZnCo2O4 and n-type semiconductor ZnO and the high specific surface area of the microspheres supported by the hierarchical structure conductive network, when this material was used to modify the glassy carbon electrode (GCE), it significantly enhanced the electrochemical sensing performance towards PCNB. Therefore, a new type of electrochemical sensor was constructed based on NiCo2O4@ZnO/ZnCo2O4 MSs and molecularly imprinted polymer (MIP) for the sensitive and highly selective detection of PCNB. Among them, the MIP membrane was fabricated by cyclic voltammetry (CV), and differential pulse voltammetry (DPV) was used to detect PCNB. Under the optimum conditions, the reduction peak current density of PCNB was linearly related to the concentration from 0.05 to 5.5 mu M with a detection limit of 8.33 nM and a good sensitivity of 6.118 mu A.mu M- 1.cmi 2. Furthermore, the proposed MIP sensor exhibited high selectivity, reproducibility, repeatability, and stability, and had been used for the detection of PCNB residues in licorice, river water, and soil samples with satisfactory results.

Automated summary

A novel hierarchical metal oxide hybrid material was developed for monitoring PCNB, showing high sensitivity and selectivity. The sensor, constructed based on molecularly imprinted polymer and cyclic voltammetry, demonstrated excellent detection performance and stability in various sample residues.