The zno/aqueous solution interface. II. mechanism of the slow process

Trimbos, H.F.A; Stein, H.N.

doi:10.1016/0021-9797(80)90309-4

Cited by 10 publications

(15 citation statements)

References 11 publications

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“…The good fit of experimental data to Values for the parameters indicate that as semiconductor mass concentration increases the OH -consumption rate increases. Consequently, as observed by other researchers, slow consumption of ions was found to be due to the presence of the semiconductor surface (16,18).…”

Section: Process Velocitysupporting

confidence: 56%

“…The semiconductor/electrolyte solution interface has been studied by comparing the P-N junction (18)(19) because of the phenomenological similarities found between semiconductor/electrolyte and P-N junctions (16,19,20,23). On each of the faces, a concentration of free charge-carriers can move through the interface, so that, in both cases, the charge currents are charge-transfer phenomena.…”

Section: Theoretical Aspectsmentioning

confidence: 99%

“…Therefore, although it is an N-type semiconductor, it behaves like a P-type one under the P-N junction equivalence (18,19,20), which must accept negative charge carriers (from the other medium in the interface) to increase its Fermi energy, as shown in scheme of Figure 1. Similarly, the electrolyte can donate electrons, decreasing its Fermi energy.…”

Section: Fermi Levelsmentioning

confidence: 99%

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Interfase Óxido/Electrolito: Fenómeno de transferencia de electrones

Fernández‐Ibáñez¹,

Malato²,

Nieves³

2000

Bol. Soc. Esp. Ceram. Vidr.

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Electron transfer on a titanium dioxide/electrolyte solution interface has been studied. As observed by other researchers on similar interfaces (TiO 2 -and ZnO-electrolyte solution), slow consumption of OH -ions was found. A theoretical model has been developed for calculating the change in Fermi energy levels of both electrolyte solution and semiconductor, showing that ion consumption from the solution is favoured by a decreased difference in their Fermi energies. A kinetic constant (υ) is found to characterise the consumption process, its value increasing with electrolyte and semiconductor mass concentrations. Furthermore, this process may be used to estimate the point of zero charge of a titanium dioxide colloidal dispersion. Keywords: Titanium dioxide, Fermi level, point of zero charge, electrophoretic mobility.Interfase Óxido/Electrolito: Fenómeno de transferencia de electrones.En este trabajo se ha estudiado un proceso de transferencia de electrones en la interfase dióxido de titanio/electrolito acuoso. Tal y como han observado otros investigadores en interfases similares (TiO 2 -y ZnO-electrolito), se ha detectado un consumo lento de iones OH -. Para dar explicación a este proceso, se ha desarrollado un modelo teórico basado en el cálculo de las energías de Fermi en el semiconductor y en el electrolito. De este modo, se demuestra que dicho consumo de iones está favorecido por una disminución de la diferencia entre ambos niveles de Fermi. Para caracterizar el proceso de consumo lento de OH -se define una constante cinética (υ), cuyo valor aumenta a medida que crece la concentración másica de semiconductor y de electrolito en la suspensión. Adicionalmente, este fenómeno proporciona una herramienta para determinar experimentalmente el punto de carga nula de la suspensión de dióxido de titanio en el medio acuoso.Palabras clave: Dióxido de titanio, nivel de Fermi, punto de carga nula, movilidad electroforética.

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Section: Process Velocitysupporting

confidence: 56%

Section: Theoretical Aspectsmentioning

confidence: 99%

Section: Fermi Levelsmentioning

confidence: 99%

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Interfase Óxido/Electrolito: Fenómeno de transferencia de electrones

Fernández‐Ibáñez¹,

Malato²,

Nieves³

2000

Bol. Soc. Esp. Ceram. Vidr.

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“…A theoretical justification for this procedure, based on a mechanism for the slow reaction which accounts for all data available at present, is given in another paper Ref. (15). b For cro, the surface charge at the pzc (pH 8.7) is taken as reference.…”

Section: Experiments At Constant Phmentioning

confidence: 99%

“…E-potentials of ZnO have been determined during the slow reaction in 0.01 and 0.001 M solutions (15), but only after 500 and 3800 min contact. In all cases investigated the E-potential does not change any more after 500 rain contact.…”

Section: F] Flihn~ndu~ -Nsmentioning

confidence: 99%

The zno/aqueous solution interface. I. Capacity of the double layer

Trimbos

Stein

1980

Journal of Colloid and Interface Science

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At the ZnO/aqueous electrolyte solution interface, three processes occur on changing the pH of the medium: (a) adsorption of H ÷ or OH-; (b) dissolution or precipitation of ZnO; (c) a slow process consuming H + or OH-, A technique is described by which these processes can be separated. When due allowance is made for the slow process and when the influence of changes in solubility is eliminated, the capacity due to adsorption of H ÷ or OH-alone can be calculated: it is significantly smaller than that found by titration, and smaller than that of the diffuse double layer. The Stern capacity is comparable to that found at AgI/aqueous electrolyte solution interfaces near the pzc.

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