engleski

Interpretation of Equilibrium at Metal Oxide Aqueous Interface Using Surface Potential Data

Surface potential (electrostatic potential at the inner Helmholtz plane of the electrical interfacial layer  0) could be measured by recently developed single crystal electrodes. Surface potential affects the state of ionic species bound directly to the surface and determines their activity coefficients. Potentiometric titrations of dispersions provide surface charge density at the 0-plane, electrokinetic measurements yield the potential at the slip plane and at the onset of diffuse layer, while the surface potential data enable calculation of the ratio of unassociated positive and negative charged groups at the surface. The simultaneous interpretation of these data enables better insight in the equilibrium within the electrical interfacial layer and thus more accurate evaluation of the equilibrium parameters. In the interpretation one is not forced to assume constant capacitance of the inner Helmholtz layer and of the thermodynamic surface equilibrium constants. Consequently, such an approach may serve for critical evaluation of the theoretical models describing the equilibrium at the interface.

electrical interfacial layer; surface potential; metal oxide

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