Arumugam Manivel

Synthesis of Ag-ZnO nanoparticles for enhanced photocatalytic degradation of acid red 88 in aqueous environment

Photocatalytic activities were found to be enhanced when noble metals were deposited on the semiconductors because the metal nanoparticles store electrons within them and in turn are recognized to act as a sink for photoinduced charge carriers, promoting interfacial charge transfer processes. This motivates us to modify the bare ZnO powder by doping with nano sized silver to yield metal-semiconductor nanocomposites by simple material syntheses route to suppress detrimental recombination of the photogenerated charge carriers. The materials were characterized by different analytical techniques and it is potentially utilized for the photocatalytic degradation of an azo dye (Acid Red 88; AR88) in the visible region (lambda>400 nm). A possible mechanism for the photocatalytic degradation of AR88 by Ag-ZnO in the absence and presence of other oxidizing agents (peroxomonosulfate (PMS), peroxodisulfate (PDS) & hydrogen peroxide (H(2)O(2))) has been proposed. The extent of mineralization of the target pollutant was also evaluated using Total Organic Carbon (TOC) analysis.

Interfacially synthesized PAni-PMo12 hybrid material for supercapacitor applications

The concept of interfacial polymerization is utilized for the synthesis of polyaniline-phosphomolybdate (PAni-PMo12) molecular hybrids and it is well characterized. The electrical conductivity of the synthesized hybrid materials increases with increase in PMo12 wt%. The synthesized hybrid materials are evaluated as the active electrode materials for supercapacitor application. Cyclic voltammetric studies of the hybrid-modified electrode shows broad parallelogram-shaped peak as an evidence for pseudo-capacitive behaviour. The galvanostatic charge-discharge studies enlighten that interfacially synthesized hybrid materials loaded with PMo12 show relatively enhanced specific capacitance values than PMo12 free samples.

Ruthenium(II) complexes incorporating carbazole–diazafluorene based bipolar ligands for dye sensitized solar cell applications

In this research work, new types of ruthenium sensitizers used in dye sensitized solar cells (DSSCs), named S3 and S4, consisting of carbazole–diazafluorene based bipolar ancillary ligands, have been synthesized and characterized by 1H NMR, UV-vis absorption spectroscopy, and elemental analysis. The energy levels and band gaps of the sensitizers were evaluated using electrochemical measurements and density functional theory (DFT) calculations. Both sensitizers show blue shifted low energy metal to ligand charge transfer bands, which could be ascertained from the relatively large dihedral angle between the secondary electron donor (carbazole) and acceptor (4,5-diazafluorene) units. The frontier molecular orbital surfaces obtained from DFT calculations revealed that the highest occupied molecular orbitals (HOMOs) of both sensitizers are dominantly populated on the secondary electron donor carbazole antenna, indicating the increased spatial separation of the HOMO away from the TiO2 surface. The DSSC fabricated using sensitizer S4 exhibited a higher photon-to-current conversion efficiency (2.11%) and these results were compared to those obtained with commercial sensitizer N719. The implications of this study may contribute to the design of new molecular architectures to be applied in DSSCs.

Electropolymerization of cobalto(5,10,15-tris(4-aminophenyl)-20-phenylporphyrin) for electrochemical detection of antioxidant-antipyrine

Porphyrins are a kind of aromatic molecules possessing unique physic-chemical properties. In this manuscript, it was thus utilized to synthesize 5,10,15-tris(4-aminophenyl)-20-phenylporphyrin and cobalto(5,10,15-tris(4-aminophenyl)-20-phenylporphyrin). In addition, conducting cobalto(5,10,15-tris(4-aminophenyl)-20-phenylporphyrin) polymeric films were successfully prepared by electropolymerization approach on glassy carbon electrode in the presence of dimethyl formamide solution and 0.1 M tetra-n-butyl ammonium perchlorate at 100 mV/s scan rate. The synthesized polymeric films were evaluated as the active electrode materials to detect an antioxidant (Antipyrine) present in pharmaceuticals and the limit of detection is ~ 74 μM.