The rate-limiting steps of the electrolysis of water solution, taking into account hydrogen evolution overpotential were considered. A functional relationship between the electrical resistivity of 3–5 dm metals and their quantization energy of atomic electrons, as well as the coordination of metal atoms and hydrogen compounds, has been revealed. The rule of selecting effective metals for cathodes has been validated. Based on these rules, a reduction-relay mechanism of the hydrogen migration process in the electrical double layer in the electrochemical reduction of TiO2+ ions to Ti3+ and Fe3+ to Fe2+ in sulfuric acid process solutions for the production of pigment titanium dioxide was proposed. The method of the multistage electrochemical reduction of Fe3+ and [TiO2+ * nH2O] in process solutions for the production of titanium dioxide was design based on this study.