METHOD OF DETERMINING THE TRUE SURFACE OF THE ELECTROLYTIC PRECIPITATES OF THE RHODIUM DEPOSITED ON THE CARBON-CONTAINING ELECTRODE BY THE METHOD OF INVERSION VOLTAMMETRY Russian patent published in 2018 - IPC G01N27/48 

FIELD: electricity; chemistry.

SUBSTANCE: invention relates to electrochemistry, namely to the study and analysis of materials by determining the electrochemical parameters for voltammetric measurements and can be used to evaluate the surface of electrodes modified with rhodium, as well as surfaces of highly developed micro- and nanoporous catalysts with precipitates of this metal. Method for determining the true surface of an electrolytic rhodium precipitate deposited on a carbon-containing electrode by the method of inversion voltammetry is that perform electrooxidation of mercury (II) ions with a concentration of 10 mg/dm³ on the surface of a carbon-containing electrode in a constant-current mode from solutions of 1M HCl at a potential E_E -1 V for 180 s and the rate of change of the potential W of 0.08 V/s. Then register the peak-point current of the mercury electrooxidation from the surface of the carbon-containing electrode I_d observed at a potential of +0.1 V of CSE (chloride silver electrode), and determine the surface of the carbon-containing electrode without rhodium precipitate S₀. Add additives of rhodium (III) ions in the concentration range of 0.03 to 0.15 mg/dm³, conduct electrooxidation of rhodium (III) ions in the presence of 10 mg/dm³ ions of mercury(II) at a potential E_E -1 V for 180 s and the rate of change of the potential W of 0.08  V/s. Register values of the peak area of electrochemical oxidation of mercury from the binary precipitate with rhodium Q₂ observed at a potential of -0.35 V. Plot a graph of the peak area of mercury electrochemical oxidation from the surface of the carbon-containing electrode Q₁ dependency on the concentration of rhodium(III) ions. By extrapolating the graph, the limit value Q₀ and determine the true surface of the electrolytic precipitate of rhodium according to the proposed formula.

EFFECT: invention makes it possible to determine the true surface of the rhodium sediment for varying degrees of filling with this metal of the surface of the carbon-containing electrode.

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