Copper oxide nanoparticles (CuO NPs) were synthesized in air by reducing copper (II) sulfate pentahydrate salt (CuSO4·5H2O) in the presence of sodium borohydride. The reaction was stabilized with Hexadecyltrimethylammonium bromide (CTAB) in a basic medium and using ultrasound waves. Different molar ratios of CTAB:Cu2+ and NaBH4:Cu2+ were explored, to optimize the synthesis conditions, and to study the stability, size, and Zeta potential of the colloidal suspension. Optimum conditions to generate spherical, stable, and monodispersed nanoparticles with hydrodynamic diameters of 36 ± 1.3 nm were obtained, using 16 mM CTAB and 2 M NaBH4 (molar ratios Cu2+:CTAB:NaBH4 of 1:6:10). X-ray diffraction (XRD) was implemented, and a monoclinic CuO crystal system was formed. This demonstrated a monoclinic crystal system corresponding to CuO. The diffraction peaks were identified and confirmed according to their selected area electron diffraction (SAED) patterns.

No abstract

No abstract

The incorporation and effective anchorage of gold nanorods in a gold (111) is applied to electrochemical detection of dopamine. Gold nanorods (AuNRs) were synthesized in dispersion and incorporated in a metal substrate mediated by self-assembled monolayers (SAMs) which act as structural anchors. Two molecular anchors, 4-mercaptobenzoic acid (4-MBA) and 4 aminothiophenol (4-ATP), are compared by charge density (Q) in desorption of the SAMs, where 4-MBA presented a greater coverage on the metal surface. Both SAMs allowed the effective confinement and communication of nanostructure to a greater or lesser extent. Characterizations were made to confirm the constructed system. First, the nanostructures synthesized in dispersion were characterized by UV-visible, transmission electron microscopy, and atomic force microscopy. Then, an electrochemical characterization of the working electrodes include impedance was made. The results focus on the molecular anchor on the activity of electrochemical sensor. Reducing the charge transfer resistance (by at least 90%) of molecularly anchored gold nanorods increases the sensitivity of the electrochemical sensor (at least 20%), the detection of dopamine was studied through a calibration curve, where better sensitivity and detection limit was obtained with the Au/4-MBA/AuNRs system compared to Au/4-ATP/AuNRs.