In this work, we have successfully synthesized core-shell structured Au-PDA@SiO2 nanospheres and decorated on reduced graphene oxide (rGO) modified glassy carbon electrode for the electrochemical detection of cefotaxime. The one-pot hydrothermal method was used to synthesis core-shell nanostructures by loading Au nanoparticles on polydopamine (PDA) coated SiO2 nanospheres. The as-prepared Au-PDA@SiO2 nanospheres were used to fabricate electrochemically reduced graphene oxide (rGO) modified glassy carbon electrode (Au-PDA@SiO2/rGO/GCE) for electrochemical determination of cefotaxime. Scanning electron microscopy, powder x-ray diffraction, transmission electron microscopy, and Fourier-transform infrared spectroscopy were used to confirm the structure and morphology of the as-prepared nanospheres. Cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS) were performed for electrochemical characterizations different modified electrodes. It was revealed that the nanocomposite modified electrodes exhibited excellent electrochemical performances for electrooxidation of target analytes and could achieve ultra-sensitive detections. A linear relationship was observed between peak currents and concentrations in the ranges of 1.0 × 10−9 to 5.0 × 10−8 M (R2 = 0.9877), and 1.0 × 10−7 to 5.0 × 10−6 M (R2 = 0.9821) for cefotaxime with a detection limit (S/N = 3) of 1.0 × 10−10 M. It can be deduced that the proposed sensor is suitable for the sensitive detection of cefotaxime in pharmaceutical samples.

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A comprehensive understanding of the catalytic decarbonylation mechanism of furfural (FF) is prominently meaningful for developing effective catalysis techniques to produce furan. Herein, possible mechanisms for FF decarbonylation over single-site and multi-site Ni/MgO surfaces were investigated using periodic density functional theory calculations. The electronic structures evidence that Ni doping can modify the electronic density of MgO and thus form favorable electronic configurations for FF adsorption. The reaction paths indicate that the single-site and multi-site catalysts result in different decarbonylation mechanisms of FF, with the latter having better catalytic activity, because the multi-site Ni/MgO has high selectivity in the C−C bond-breaking-induced pathway. Furthermore, potential decarbonylation catalysts doped by diverse metals over the MgO surface were examined. It is proved that Ni/MgO has excellent decarbonylation performance among these transition or noble metal-doped catalysts, and it is even comparable to the Pt/MgO catalyst.