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HORIKOSHI, Toru; YOSHIMURA, Syunichi; Kubota, Naoji; Satô, Eiichi

doi:10.1246/nikkashi.1983.1118

Cited by 9 publications

(4 citation statements)

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“…This value is in reasonable agreement with the slope of ∼0.1 V per decade determined by Gaur and Schmid for polycrystalline gold in 0.1 M HClO 4 containing 0.8 mM chloride but twice as large as the value of 0.054 V per decade reported in the studies of Ye et al and in rotating disk electrode studies. − The latter may be caused by the less well-defined mass transport conditions in our experiment. For potentials between 1.10 and 1.20 V, the current density deviates from the Tafel behavior and the slope is significantly lower, indicating a crossover to diffusion-limited dissolution.…”

Section: Resultssupporting

confidence: 92%

Real-Time Surface X-ray Scattering Study of Au(111) Electrochemical Dissolution

et al. 2010

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Direct in situ surface X-ray scattering studies of electrochemical dissolution at technologically relevant rates are presented using Au(111) electrodes in acidic chloride-containing solutions as an example. The dissolution process was investigated with high time resolution by monitoring the time-dependent X-ray intensity at selected positions in reciprocal space and by simultaneously recording high-quality electrochemical data. With increasing electrode potential, transitions from step-flow to layer-by-layer dissolution, manifesting as layering oscillations in the X-ray intensity as well as in electrochemical current−time transients, are observed prior to surface passivation. A quantitative analysis based on an atomic-scale structural model reveals that the dissolution process proceeds via progressive vacancy island nucleation in the whole active dissolution regime with next-layer nucleation occurring at comparatively low critical coverages between θc = 0.29 and θc = 0.44. This dissolution behavior shows the same characteristics as the intermediate “smooth multilayer growth” regime recently introduced in kinetic growth theories.

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Section: Resultssupporting

confidence: 92%

Real-Time Surface X-ray Scattering Study of Au(111) Electrochemical Dissolution

et al. 2010

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“…Elucidating the dissolution mechanism of noble metals is important for both industrial applications and fundamental science. Gold is known to have an excellent chemical stability and is widely used in industry and as an accessory material. , It becomes unstable and dissolves in the positive potential region, especially in solutions containing Cl - . − Recently, we investigated in detail the anodic dissolution process of Au(111) in HClO 4 solution containing various concentrations of Cl - based on electrochemical quartz crystal microbalance (EQCM) measurements and clearly showed that gold dissolves through a 3e - mechanism in the positive potential region. A number of issues, especially the surface states of the gold electrode during the anodic dissolution process, are, however, still unclear.…”

Section: Introductionmentioning

confidence: 99%

Anisotropic Dissolution of an Au(111) Electrode in Perchloric Acid Solution Containing Chloride Anion Investigated by in Situ STMThe Important Role of Adsorbed Chloride Anion

Ishibashi

Uosaki

1998

Langmuir

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The anodic dissolution process of Au(111) in a 0.1 M perchloric acid (HClO4) solution containing chloride anion (Cl-) was investigated using an in situ scanning tunneling microscope. The initial dissolution of gold was observed at the step sites when the electrode potentials became more positive than +1.0 V. The rate of the anodic dissolution increased as the potential became more positive. When the potential became more positive than +1.35 V, dissolution on the terraces was also observed. The dissolution of Au(111) anisotropically proceeds in a layer-by-layer mode. Step lines along the [110] direction, which were found in the double-layer region, disappeared, and ones along the [211] direction were newly formed during the dissolution process. The gold surface became rougher when the electrode potential became more positive than +1.45 V, where anodic dissolution and oxide formation simultaneously took place. The gold surface was completely passivated at +1.7 V. The mechanism for the anisotropic dissolution is discussed in relation to the structure of the chloride adlayer on the Au(111) electrode surface.

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“…Their study also pointed out that the evolution of O 2 can cause the passivation of gold, which proceeded in parallel with the dissolution of gold caused by chloride ions, probably due to a competitive adsorption between an oxygen species and chloride . The generated O 2 reacted with the generated gold complex (AuClOH – ) to form a film of passivation product on the surface of gold . The passivation product was identified as Au(OH) 3 by measuring the ratio Au/(O + H 2 O) .…”

Section: Resultsmentioning

confidence: 99%

Study of Gold Leaching Behavior in the Chlorination Process from Waste Printed Circuit Boards

Wang

Zhou

Lü

2020

ACS Sustainable Chem. Eng.

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Waste printed circuit boards (WPCBs) contain certain amounts of valuable metals such as gold, and so recycling the gold from WPCBs is necessary. Based on our previous study, gold can be selectively leached in a NaClO3–NaCl–H2SO4 system. But the highest leaching rate of gold was identified as approximately 92.8%, and it was difficult to achieve higher rates by controlling the conditions of temperature, time, and concentrations of H2SO4, NaCl, and NaClO3. This reveals that the leaching behavior of gold in the chlorination process is the key to improve the gold leaching rate. Hence, the leaching behaviors of gold at different concentrations of NaClO3, NaCl, and H2SO4 were evaluated in this study. The results showed that (1) the concentrations of NaCl and H2SO4 had no significant effect on the forms of the complex species of gold; (2) the dissolution and passivation of gold proceeded in parallel with increasing the potential of the solution; (3) O2 was inevitably produced in the present reaction, leading to the passivation of gold; and (4) the passivation product was identified as Au(OH)3. The results presented in this paper provided a theoretical reference for recycling gold by the chloride method and promoted the development of chlorination technology.

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Cited by 9 publications

References 0 publications

Real-Time Surface X-ray Scattering Study of Au(111) Electrochemical Dissolution

Real-Time Surface X-ray Scattering Study of Au(111) Electrochemical Dissolution

Anisotropic Dissolution of an Au(111) Electrode in Perchloric Acid Solution Containing Chloride Anion Investigated by in Situ STMThe Important Role of Adsorbed Chloride Anion

Study of Gold Leaching Behavior in the Chlorination Process from Waste Printed Circuit Boards

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