8 research outputs found
Polypyrrole–NiO hybrid nanocomposite films: highly selective, sensitive, and reproducible NO2 sensors
Spray deposited NiOx films on ITO substrates as photoactive electrodes for p-type dye-sensitized solar cells
Spray deposition followed by sintering of nickel oxide (NiO x ) nanoparticles (average diameter: 40 nm) has been chosen as method of deposition of mesoporous NiO x coatings onto indium tin oxide (ITO) substrates. This procedure allows the scalable preparation of NiO x samples with large surface area (~103 times the geometrical area) and its potential for applications such as electrocatalysis or electrochemical solar energy conversion, which require high electroactivity in confined systems. The potential of these NiO x films as semiconducting cathodes for dye-sensitized solar cell (DSC) purposes has been evaluated for 0.3–3-μm-thick films of NiO x sensitized with erythrosine B (ERY). The electrochemical processes involving the NiO x coatings in the pristine and sensitized states were examined and indicated surface confinement as demonstrated by the linear dependence of the current densities with the scan rate of the cyclic voltammetry. Cathodic polarization of NiO x on ITO can also lead to the irreversible reduction of the underlying ITO substrate because of the mesoporous nature of the sintered NiO x film that allows the shunting of ITO to the electrolyte. ITO-based reduction processes alter irreversibly the properties of charge transfer through the ITO/NiOx interface and limit the range of potential to NiO x coatings sintered for DSC purposes.Science Foundation IrelandAM
Corrosion studies of PPy/Ni organic–inorganic hybrid bilayer coatings on commercial carbon steel
© 2014, Springer-Verlag Berlin Heidelberg. Electrodeposition of polypyrrole (PPy) was achieved on AISI 1018 carbon steel (CS) using a constant potential regime and cyclic voltammetry techniques evaluating different synthesis parameters, in monomer-containing oxalic acid solutions. Thereafter, CS PPy/Ni bilayer films were produced by Ni deposition onto PPy films using a potentiostatic method. The electrochemical performance of PPy/Ni-coated carbon steel systems was investigated in 3.0 wt% NaCl solutions. For this purpose, scanning Kelvin probe (SKP), open-circuit potential (Eocp), polarization curves, and cyclic voltammetry techniques were used. The influence of electro-synthesis method and parameters were analyzed. It was found that the deviation in the Volta potentials is correlated to the interfacial interaction between the PPy/Ni bilayer coating and substrate. Considering both experimental methods to obtain PPy/Ni coatings, a more effective protection against corrosion can be formed when potentiodynamic (cyclic voltammetry) and potentiostatic techniques are combined.Peer Reviewe