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Silver sulphide, Ag2S, layers on the surface of polypropylene (PP) film was formed by chemical bath deposition method (CBD). Film samples were characterised by X-ray photoelectron spectroscopy (XPS), attenuated total reflection Fourier transform infrared (ATR-FTIR) spectroscopy, scanning electron microscopy (SEM), atomic force microscopy (AFM), and X-ray diffraction analysis (XRD). The surface morphology, texture, and uniformity of the silver sulphide layers were formed on PP surface dependent on the number of polymer immersions in the precursor solution. XPS analysis confirmed that on the surface of the polypropylene film, a layer of Ag2S was formed. ATR-FTIR and FTIR spectra analysis showed that the surface of Ag2S layers is slightly oxidized. All prepared layers gave multiple XRD reflections, corresponding to monoclinic Ag2S (acanthite). The Ag2S layer on polypropylene was characterized as an Ag+ion selective electrode in terms of potential response and detection limit. The electrode was also tested as an end-point electrode for argentometric titration of thiamine hydrochloride.

MoO2 films were prepared by electrodeposition under potential controlled conditions from an aqueous alkaline solution of sodium molybdate. Optical microscopy showed that films of different morphology were deposited. The surface roughness and grain size were determined by atomic force microscopy. The characterization of as-deposited films by X-ray diffraction analysis revealed their amorphous nature. The optical constants of films were derived from transmittance spectra recorded in the 310–1100 nm wavelength range. All films were highly absorptive and showed a direct band to band transition. From the absorption edge data, the values of the optical band gap E g and the Urbach energy E U were determined based on Tauc’s model. The influence of film thickness on the extinction coefficient k, refractive index n, absorption coefficient a and the band gap energy E g was studied.

Thin MoO 2 films were electrodeposited on a selenium pre-deposited SnO 2 |glass plate. The photoelectrochemical properties of MoO 2 films were investigated in 0.1 M Na 2 SO 4 solution by the ultraviolet-visible spectrophotometry, linear sweep voltammetry, and altering current impedance measurement techniques. It was found that under illumination with the incident light of λ=366 nm, the photo response of the MoO 2 |SnO 2 |glass electrode resulted from the MoO 2 layer, while the SnO 2 layer served as a sink for photogenerated charge carriers. The MoO 2 film exhibited ntype conductivity. A schematic band structure diagram of MoO 2 in 0.1 M Na 2 SO 4 solution was constructed. The flat band potential (E fb ), the donor concentration (N D ), the photogeneration current efficiency depended on MoO 2 film thickness. The [Fe(CN) 6 ] 4−/3− redox PEC cell with MoO 2 | SnO 2 |glass plate as a photoanode was constructed. Power output characteristics such as the open circuit voltage (V OC ), short circuit current (I SC ), the fill factor (FF), and the lightto-electrical conversion efficiency (η) were determined. The maximum light-to-electrical conversion efficiency exhibited by the PEC cell was 0.94 %.

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Preliminary results regarding the electrochemical behavior of Se(IV) in sodium citrate solution on a polycrystalline SnO 2 electrode are presented. A schematic diagram of the energy levels for an n-type SnO 2 electrode in contact with the working electrolyte was constructed. The results of cyclic voltammetry (CV) show that SeO 3 2− reduction occurs through a surface state in a complex multistep pathway. After a minute amount of Se is deposited, the electrode is expected to behave locally like a Schottky diode in contact with the solution. CV analysis and current transient results indicate that selenium growth on the polycrystalline SnO 2 surface proceeds without nucleation. A thin Se film obtained at a potential of −0.8 V vs. Ag|AgCl, KCl (sat) was analyzed by lateral force and atomic force microscopy.