“…A relative shift of about 0.5 eV is observed for the Ag° oxidation state towards high energy as compared to Ag + state. All these experimental findings are much in streak with existing values of Ag 2 S 28–30 .Figure 3XPS spectrum of Ag 2 S nanoparticles ( a ) survey spectrum ( b , c ) High resolutionspectra of Ag and S.…”
A facile approach of chemical bath deposition was proposed to fabricate direct synthesis of silver sulphide (Ag
2
S) on nickel (Ni) mesh without involvement for binders for supercapacitor electrodes. The phase purity, structure, composition, morphology, microstructure of the as-fabricated Ag
2
S electrode was validated from its corresponding comprehensive characterization tools. The electrochemical characteristics of the Ag
2
S electrodes were evaluated by recording the electrochemical measurements such as cyclic voltammetry and charge/discharge profile in a three electrode configuration system. Ag
2
S employed as working electrode demonstrates notable faradaic behaviour including high reversible specific capacitance value of 179 C/g at a constant charge/discharge current density of 1 A/g with high cyclic stability which is relatively good as compared with other sulphide based materials. The experimental results ensure fabricated binder-free Ag
2
S electrodes exhibits better electrochemical performance and suitable for potential electrodes in electrochemical energy storage applications.
“…A relative shift of about 0.5 eV is observed for the Ag° oxidation state towards high energy as compared to Ag + state. All these experimental findings are much in streak with existing values of Ag 2 S 28–30 .Figure 3XPS spectrum of Ag 2 S nanoparticles ( a ) survey spectrum ( b , c ) High resolutionspectra of Ag and S.…”
A facile approach of chemical bath deposition was proposed to fabricate direct synthesis of silver sulphide (Ag
2
S) on nickel (Ni) mesh without involvement for binders for supercapacitor electrodes. The phase purity, structure, composition, morphology, microstructure of the as-fabricated Ag
2
S electrode was validated from its corresponding comprehensive characterization tools. The electrochemical characteristics of the Ag
2
S electrodes were evaluated by recording the electrochemical measurements such as cyclic voltammetry and charge/discharge profile in a three electrode configuration system. Ag
2
S employed as working electrode demonstrates notable faradaic behaviour including high reversible specific capacitance value of 179 C/g at a constant charge/discharge current density of 1 A/g with high cyclic stability which is relatively good as compared with other sulphide based materials. The experimental results ensure fabricated binder-free Ag
2
S electrodes exhibits better electrochemical performance and suitable for potential electrodes in electrochemical energy storage applications.
“…Silver foils were immersed overnight in either air-saturated or Ar-purged Na 2 S solutions, and their surfaces imaged under visible light. In aerobic conditions a dark gray sulfidic scale forms, possibly Ag 2 S (29) (Fig. 4A).…”
Among the many new engineered nanomaterials, nanosilver is one of the highest priority cases for environmental risk assessment. Recent analysis of field samples from water treatment facilities suggests that silver is converted to silver sulfide, whose very low solubility may limit the bioavailability and adverse impact of silver in the environment. The present study demonstrates that silver nanoparticles react with dissolved sulfide species (HS−, S2−) under relevant but controlled laboratory conditions to produce silver sulfide nanostructures similar to those observed in the field. The reaction is tracked by time-resolved sulfide depletion measurements to yield quantitative reaction rates and stoichiometries. The reaction requires dissolved oxygen, and it is sensitive to pH and natural organic matter. Focusedion-beam analysis of surface films reveals an irregular coarse-grained sulfide phase that allows deep (> 1 μm) conversion of silver surfaces without passivation. At high sulfide concentrations, nanosilver oxysulfidation occurs by a direct particle-fluid reaction. At low sulfide concentration, quantitative kinetic analysis suggests a mechanistic switch to an oxidative dissolution/precipitation mechanism, in which the biologically active Ag+ ion is generated as an intermediate. The environmental transformation pathways for nanosilver will vary depending on the media-specific competing rates of oxidative dissolution and direct oxysulfidation.
“…The existence of SO 22 4 was detected by Saber et al 26 when studying the tarnish mechanism of silver on immersion for 3 h in 0?1M NaOH containing Na 2 S using X-ray photoelectron spectroscopy. No details were given of the mechanism of its formation from the sulphide ion.…”
The electrochemical behaviour of silver in 0?5M NaOH solution containing different concentrations (0?0005-0?007M) of sodium sulphide was studied using cyclic voltammetry, potentiodynamic, and current transient techniques. The anodic sweep of the voltammogram in NaOH was characterised by the appearance of three anodic peaks A 3 , A 4 and A 5 that are related to the formation of AgO 2 , Ag 2 O and Ag 2 O 2 on the electrode surface. The presence of Na 2 S in NaOH solution resulted in the appearance of two additional anodic peaks A 1 and A 2 . These two peaks are related to the formation of Ag 2 S and S, respectively. The addition of Na 2 S also increases the heights of the anodic peaks A 3 , A 4 and A 5 . The increase in the current density of the anodic peaks A 3 and A 4 is mainly due to surface enlargement resulting from pitting and the precipitation of sulphur on the electrode surface. Also, the large increase in the current density of the anodic peak A 5 is due to the formation of the soluble SO 22 4 compound. The morphology of the electrode surface was examined by scanning electron microscopy. Characterisation of the corrosion products formed anodically on the electrode surface was undertaken using X-ray diffraction analysis. Potentiostatic current-time transients showed that the formation of Ag 2 S, S and Ag 2 O layers involves a nucleation and growth mechanism under diffusion control.
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