RESUMEN
In this paper, Co-Al layered double hydroxides (LDHs), Co-Al LDHs/poly(o-phenylenediamine) (PoPD) and Ag nanoparticles decorated Co-Al LDHs/PoPD (Ag@Co-Al LDH/PoPD) samples were prepared. The as-prepared samples were characterized by XRD, Raman, XPS, FT-IR, DRS-UV-Vis, PL and TGA techniques. The salient features of morphology and size of the samples were determined using FESEM, and HR-TEM. Then, the samples were coated on glassy carbon electrode (GCE) and employed for sensing of 4-nitrophenol (4-NP), 2,4-dinitrophenol (2,4-DNP)) and uric acid (UA). It was found that Ag@Co-Al LDH/PoPD/GCE showed superior electrochemical sensing behaviour than other modified electrodes. It exhibits the detection limit (DL) of 63 nM, 50 nM and 0.28 µM for 4-NP, 2,4-DNP and UA respectively.
RESUMEN
Ni0/NiO (nickel/nickel oxide) core-shell nanostructures were synthesized through a facile combustible redox reaction. Remarkably, the hetero-phase boundary with different crystalline orientations offered dual properties, which helped in bifunctional catalysis. Presence of a metallic Ni phase changed physicochemical properties and some emerging applications (magnetic properties, optical conductivity, electrochemical sensitivity, catalytic behaviour) could be foreseen. Moreover, formation of a NiO layer on metal surface prevented magnetism-induced aggregation, arrested further oxidation by hindering oxygen diffusion, and acted as a good sorbent to enhance the surface adsorption of the analyte. Hexagonal Ni/NiO nanostructures manifested well-defined ferromagnetic behavior and the catalyst could be collected easily at the end of the catalytic reduction. Ni/NiO core-shell catalysts at the nanoscale had outstanding catalytic performance (reduction of 4-nitrophenol to 4-aminophenol) compared with pure NiO catalysts beyond a reaction time of â¼9 min. The estimated sensitivity, limit of detection and limit of quantification towards the electrochemical sensing of serotonin were 0.185, 0.43 and 1.47 µM µA-1, respectively. These results suggest that a bifunctional Ni/NiO nanostructure could be a suitable catalyst for electrochemical detection of serotonin and reduction of 4-nitrophenol.
RESUMEN
A series of acyclic Schiff base chromium(III) complexes were synthesized with the aid of microwave irradiation method. The complexes were characterized on the basis of elemental analysis, spectral analysis such as UV-Visible, Fourier transform infrared (FT-IR), nuclear magnetic resonance (NMR), electron paramagnetic resonance (EPR) spectroscopies and electrospray ionization (ESI) mass spectrometry. Electrochemical analysis of the complexes indicates the presence of chromium ion in +3 oxidation state. Cr (III) ion is stabilized by the tetradentate Schiff base ligand through its nitrogen and phenolic oxygen. From the spectral studies it is understood that the synthesized chromium(III) complexes exhibits octahedral geometry. Antimicrobial activity of chromium complexes was investigated towards the Gram positive and Gram negative bacteria. In the present work, an attempt was made to fabricate a new kind of modified electrode based on chromium Schiff base complexes for the detection of catechol at nanomolar level.