Facile synthesis of palladium nanoparticles loaded on zirconia/porous carbon nanocomposites via a ternary synergistic strategy for ultrasensitive adrenaline detection.

BACKGROUND

Adrenaline, a critical neurotransmitter and hormone, is closely associated with cardiovascular diseases, diabetes, and neurological disorders when its levels become dysregulated. However, the development of ultrasensitive and selective electrochemical sensors for adrenaline remains challenging, underscoring the need for advanced synergistic nanocomposites.

RESULTS

We report a novel ternary nanoarchitecture, palladium-zirconium oxide@porous carbon (Pd-ZrO2@PCs) composites, constructed through a ternary synergistic strategy for the ultrasensitive detection of adrenaline. In this work, the UiO-66 precursor (where "UiO" refers to the University of Oslo) was first synthesized via a conventional hydrothermal method. Pd nanoparticles (NPs) were then incorporated into the pores and deposited onto the surface of UiO-66 using a solution impregnation-chemical reduction process to form Pd-UiO-66. Subsequent carbonization under an inert atmosphere converted the zirconium metal nodes of UiO-66 into ZrO2 and the organic linkers into porous carbon, yielding the Pd-ZrO2@PCs nanocomposite. This ternary composite exhibited remarkable electrocatalytic performance due to the intrinsic catalytic activity of Pd NPs, the high conductivity of porous carbon, and the enhanced electron-transfer kinetics afforded by ZrO2. As a result, the developed sensor achieved a wide linear detection range of 3.5-600 μM, a high sensitivity of 2.03 μA μM-1 cm-2, a low detection limit of 0.07 μM (S/N = 3), and excellent anti-interference characteristics. Spike-and-recovery experiments using human serum samples yielded recoveries ranging from 98.68 % to 104.91 %, demonstrating its potential for clinical application.

SIGNIFICANCE: The Pd-ZrO2@PCs composite enables ultrasensitive and selective adrenaline sensing through the synergistic contributions of Pd NPs, ZrO2, and porous carbon. This strategy not only provides a reliable platform for clinical adrenaline detection but also offers a promising approach for designing high-performance nanocomposites for broader biomolecular sensing applications.