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Pd nanoparticle catalysts supported by thiolated graphene oxide (tGO) on a glassy carbon electrode (GCE), and denoted as tGO-Pd/GCE, are used in this study for the electrochemical determination of hydroxylamine and hydrazine. The physicochemical properties of tGO-Pd were characterized by transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS) and electrochemical impedance spectroscopy (EIS). They showed strong catalytic activity toward the oxidation of hydroxylamine and hydrazine. Cyclic voltammetry (CV) and amperometry were used to characterize the sensors' performances. The detection limits of hydroxylamine and hydrazine by tGO-Pd/GCE were 0.31 and 0.25 microM (s/n = 3), respectively. The sensors' sensitivity, selectivity, and stability were also investigated.

Poly(3,4-ethylenedioxythiophene)-(PEDOT)-functionalized reduced graphene oxide (rGO) with MnO2 nanoparticles (MnO2/PEDOT/rGO) was prepared using electrochemical methods. The MnO2/ PEDOT/rGO was obtained through the electrochemical reduction of PEDOT/GO and under electrochemical treatment in KMnO4. The PEDOT/rGO and MnO2/PEDOT/rGO were characterized by several instrumental and electrochemical methods. The electrocatalytic 02 reduction for both electrodes was investigated via cyclic and hydrodynamic voltammetry in 0.1 M KOH aqueous solutions. The kinetic analysis in comparison to PEDOT/rGO a significant enhancement was found for the MnO2/PEDOT/rGO. The proposed main path in the oxygen reduction reaction (ORR) mechanism on the MnO2/PEDOT/rGO was the direct four-electron transfer process with faster transfer kinetic rate. The better ORR kinetics were obtained due to the excellent composite formation and well attachment of MnO2 NPs within oxide form. The PEDOT/rGO was less stable for long term use than MnO2/PEDOT/rGO.

The electrocatalytic activities of metal-decorated graphene oxide (GO) catalysts were investigated. Electrochemically reduced GO-S-(CH2)4-S-Pd [ERGO-S-(CH2)4-S-Pd] and GO-S-(CH2)4-S-PdAg alloy [ERGO-S-(CH2)4-S-PdAg] were obtained through the electrochemical reduction of GO-S-(CH2)4-S-Pd and GO-S-(CH2)4-S-PdAg in a pH 5 PBS solution. It was demonstrated that the application of ERGO-S-(CH2)4-S-Pd and ERGO-S-(CH2)4-S-PdAg used in a modified GCE improves the electrocatalytic oxidation of formic acid. The addition of an Ag nanoparticle with a carbon chain-Pd in the electrode provides an electrode with very interesting properties for the electrocatalytic oxidation of formic acid. The ERGO-S-(CH2)4-S-Pd and ERGO-S-(CH2)4-S-PdAg were characterized via X-ray photoelectron spectroscopy (XPS), scanning electron microscopy (SEM) and transmission electron microscopy (TEM). ERGO-S-(CH2)4-S-Pd and ERGO-S-(CH2)4-S-PdAg can be employed for the electrocatalytic oxidation of formic acid. The electrochemical behaviors of this electrode were investigated using cyclic voltammetry (CV), chronoamperometry (CA) and electrochemical impedance spectroscopy (EIS).