engleski

Determining a Point of Zero Potential of Single-Crystal Electrode/Inert Electrolyte Interface

Most of the environmentally important processes occur at the specific hydrated mineral faces. Their rates and mechanism are in part controlled by the interfacial electrostatics, which are quantitatively described using point of zero potential. In this report, we showed how this descriptor can be obtained in a single-crystal electrode potentiometric titration experiment, assuming lack of specific sorption of electrolyte ions and stable electrode response to the change in potential-determining ions concentration. Method is based on determining common-intersection point of electromotive force of the cell at a different ionic strength. Presented method is complementary to the previously reported hysteresis method [P. Zarzycki, S. Chatman, T. Preočanin, K.M. Rosso Langmuir 27 (2011) 7986-7990], and may be applied to the systems whose electrostatic response is too fast to produce a hysteresis loop in a cyclic titration experiment. Methodology is illustrated by for specific crystal faces of rutile, hematite, silver chloride and bromide.

single-crystal electrode; point of zero potential; common intersection point; point of zero salt effect; surface potential

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