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In the current study, bimetallic-organic gel (ZrFe-MOGs) were rapidly prepared without using any toxic or harmful organic solvent, and new bimetallic oxide ZrFeO x were prepared by roasting ZrFe-MOGs directly. Then ZrFeO x nanoparticles were combined with 3D RGO/MWCNTs by a solvothermal method to synthesize 3D RGO/MWCNTs@ZrFeO x hybrid. Due to its three-dimensional structure, large electroactive surface area and more active sites, and excellent conductivity, the electrocatalytic activity of the modified electrode for the oxidation of dopamine (DA) and paracetamol (PAT) was effectively improved, and the overlap of anode peak due to their closer electrochemical oxidation potentials was solved. Under optimal conditions, the linear responses to DA and PAT were in the range of 1 − 12 μM, 12 − 180 μM and 1 − 14 μM, 14 − 190 μM, respectively. The detection limits (S/N = 3) for DA and PAT were 0.230 and 0.212 μM, respectively. The optimized 3D RGO/MWCNTs@ZrFeO x has good reproducibility, repeatability, stability, selectivity, and can be used to detect DA and PAT simultaneously. In addition, the proposed RGO/MWCNTs@ZrFeO x sensor exhibited a good recovery factor in the analysis of real drug and serum samples with a relative standard deviation of less than 5 %. Importantly, the electroactive area of 3D RGO/MWCNTs@ZrFeO x , and the 2 H+/2e- mechanism of DA and PAT oxidation on the surface of 3D RGO/MWCNTs@ZrFeO x were discussed, which provided a theoretical basis for further understanding of this redox process. [Display omitted] • 3D RGO/MWCNTs@ZrFeO x hybrid was synthesized based on the bimetallic-organic gel (ZrFe-MOG). • The proposed 3D RGO/MWCNTs@ZrFeOx can be used to detect DA and PAT simultaneously. • The proposed sensor had good reproducibility, repeatability, stability, selectivity. • The developed sensor exhibited a good recovery rate in the analysis of real drug and serum samples. [ABSTRACT FROM AUTHOR]

[Display omitted] Schematic diagram of the fabrication process of NiO@LaMnO 3 /MWCNTs/GCE and oxidation mechanisms of AA. • A novel NiO@LaMnO 3 /MWCNTs core–shell p-p homotype heterojunction has been designed. • NiO@LaMnO 3 /MWCNTs/GCE presented satisfying selectivity, repeatability, anti-interference ability. • The electrochemical signal of AA is amplified by the NiO@LaMnO 3 /MWCNTs core–shell heterojunction. A novel core–shell p-p homotype heterojunction based on NiO@LaMnO 3 and multi-walled carbon nanotubes (NiO@LaMnO 3 /MWCNTs) has been designed and synthesized via electrostatic self-assembly method. The phase compositions and morphology were verified by X-ray diffraction (XRD), scanning electron microscope (SEM), transmission electron microscope (TEM). A series of electrochemical tests showed that NiO@LaMnO 3 /MWCNTs modified electrode had a magnifying effect on the electrochemical response signal of ascorbic acid (AA) detection. The current response is linearly increased in the range of 2.60–36.44 μmol/L with the linear regression equation being I (μA) = 0.5902 C (μmol/L) + 1.4407 (R2 = 0.9909), and the detection limit (S/N = 3) being 2.41 μmol/L. Moreover, NiO@LaMnO 3 /MWCNTs/GCE electrochemical sensor presented satisfying selectivity, stability, repeatability, and can be used to analyze the AA concentration in real daily drinks. The relatively excellent electrocatalytic activity should be attributed to high electroactive surface area, well-matched core–shell structure and synergetic effect of p-p homotype heterojunction. This work offer applicable guidelines for the design of core–shell p-p heterojunction electrode materials for the application of electrochemical sensor. [ABSTRACT FROM AUTHOR]