Role of vanadium ions on structural, optical and electrochemical properties of the vanadate-lead glasses

• The increase of the V2O5 content produces pyrovanadate and orthovanadate units.
• The vanadium species have significant effect on the resonance lines.
• A decrease of the optical band gap energy

New different series of xV2O3∙(100 − x)[4PbO2·Pb] glasses were prepared by melt-quenching method in a wide range of compositions defined by the parameter x = 0–30 mol% V2O5. InfraRed (IR) data reveal that by increasing the V2O5 content, the glass network was transformed into a mixture of modified [VO4] structural units, namely pyrovanadate and orthovanadate ones. The UltraViolet–Visible (UV–VIS) spectra show that addition of V2O5 produces a gradual shift of the absorption edge towards the higher wavelength side (indicating the increase in concentration of vanadyl species) and a decrease of the gap energy.The shape of the Electron Spin Resonance (ESR) spectra changes with increasing the V2O5 content suggesting that the interactions between vanadium centers strongly depend on x parameter which plays an important role. A hyperfine structure becomes visible in the glass with x = 20 mol% V2O5 suggesting modifications of the glass structure caused by the network modifier. If the network is moderately disrupted the formation of Pb+ 2–V+ 4 pairs was coupled through the oxygen atom or the interactions within V+ 4–O–V+ 5 chains mask hyperfine structure.The shape of cyclic voltammograms, redox waves and good reversibility of the x = 20 mol% V2O5 glassy electrode depends on the electrolyte acidity and electrochemically active species present in the glass network.