In this paper, Ag–Pd bimetallic nanoparticles uniformly distributed on reduced graphene oxide (rGO) were synthesized by redox reaction between Pd²⁺, Ag⁺and GO, and were characterized by X-ray diffractometry, field emission scanning electron microscopy, electrochemical impedance spectroscopy and thermal gravimetric analyses. A novel electrochemical sensor was constructed based on these nanocomposites using glassy carbon as a substrate. Under optimal conditions, the linear ranges were 0.50–300.00 μM for PA and 1.00–300.00 μM for 4-AP, with the detection limits of 0.23 μM for PA and 0.013 μM for 4-AP, respectively. This sensor was successfully applied to the determination of PA in pharmaceutical formulations and gave satisfactory results with a lower detection limit, wider linear range and good reproducibility.

Au@Pd core–shell nanoplates were synthesized successfully through the heterogeneous, epitaxial growth of Au on Pd nanoplates. The Pd nanoplates were prepared by reducing H₂PdCl₄ with PVP, and then served as seeds for the nucleation of Au atoms formed by reducing HAuCl₄ with citric acid. Characterization of the as-prepared Au–Pd nanoplates by scanning electron microscopy revealed that a Au shell was formed around the Pd nanoplate. In order to avoid agglomeration, the Au@Pd nanoplates were loaded onto reduced graphene to give a Au@Pd/rGO nanohybrid, which exhibited excellent electrocatalytic activity towards the redox of hydroquinone (HQ) and catechol (CC) simultaneously. The linear detection ranges were 0.01–400.00 μM for HQ and 0.10–400.00 μM for CC, with detection limits of 0.01 μM for HQ and 0.10 μM for CC. Because of the excellent performance, lower detection, wider linear range, and better selectivity, the prepared Au@Pd/rGO nanohybrid has more potential applications and has an expected application in the electrochemical sensing field.