In this study we report a one-step procedure for the fabrication of Pd–Ag bimetallic nanoparticles on the surface of a graphene oxide (rGO) support. A controlled reduction of Pd²⁺ and Ag⁺ ions on an rGO support was achieved by using a methyl ammonium borane reducing agent. The fabricated Pd–Ag/rGO bimetallic nanocomposites were characterized by X-ray diffraction (XRD), Transmission electron microscopy (TEM) and Fourier-transform infrared spectroscopy (FT-IR). A Pd–Ag/rGO based electrochemical sensor was fabricated by immobilizing the as-prepared Pd–Ag/rGO bimetallic nanocomposites on to a bare glassy carbon electrode (GCE). The resulting Pd–Ag/rGO/GCE electrochemical sensor was proved to be ultrasensitive and selective towards the detection of acetaminophen (APAP) in the presence of etilefrine (ET). The linear dynamic range (LDR) for the detection of APAP was found to be 1.2–30 nM with a good limit of detection (LOD) and the limit of quantification (LOQ) of 3.26 nM and 13 nM, respectively. The newly prepared Pd–Ag/rGO/GCE-modified electrode makes a good analytical tool for the accurate determination of APAP either in its pristine conditions or in the presence of both real human samples and pharmaceutical formulations. The convenient fabrication protocol shown here can be extendable to other types of bimetallic configurations for various electrochemical sensing applications.

The present report demonstrates the development of a Pt–Ni/rGO composite electrochemical sensor for the detection of dopamine.

Use of Pt-based electro-catalysts for the oxygen reduction reaction (ORR) is a major hindrance in large-scale application of proton exchange membrane fuel cells (PEMFCs). Hence, new, cost-effective and high performance electro-catalysts are required for the commercial success of PEMFCs. In this work, a Pt-free magnesium oxide (MgO) decorated multi-layered reduced graphene oxide (MLGO) composite is tested as an electro-catalyst for the ORR. The ORR activity of MgO/MLGO in terms of diffusion-controlled current density is found to be superior (6.63 mA per cm²-geo) than that of in-house prepared Pt/rGO (5.96 mA per cm²-geo) and commercial Pt/C (5.02 mA per cm²-geo). The applicability of less expensive MgO/MLGO not only provides a new electro-catalyst but also provides a new direction in exploring metal oxide-based electro-catalysts for the ORR.