Evaluating the accuracy of electrochemical techniques in predicting the industrial alkaline hydrogen production electrolyzer performance: Impacts of electrocatalyst surface changes

Abstract

This study explored the effectiveness of electroanalytical techniques, encompassing cyclic voltammetry, Tafel standards, and chronoamperometry, in predicting hydrogen production in industrial-scale electrolyzers. A three-electrode cell was utilized to investigate four electrodes made of pure Ti and nanostructured TiO₂, Ag, and Ag+TiO₂, which were synthesized and applied as hydrogen source cathode electrodes in an industrial setting. The findings indicated that the sequence of electrode activity derived from cyclic voltammetry measurements (TiO₂>Ti>Ag>Ag+TiO₂) differed markedly from that observed at the industrial scale (TiO₂>Ag>Ag+TiO₂>Ti). The Tafel slope for each coated electrocatalyst yielded two distinct scan rate values, while a singular value was observed for pure Ti. Chronoamperometry studies indicated that the performance arrangement of the electrodes resembled that found in industrial systems. The observed differences in behavior between chronoamperometry and cyclic voltammetry studies can be explained by the fact that chronoamperometry is based on concentration gradients, while cyclic voltammetry is based on change in potential. All nanostructured electrodes exhibited non-Cottrellian behavior, indicating that hydrogen evolution from the nanoparticle-enriched electrodes significantly differed from that expected from the pure one. Nanoparticle-modified electrode specialists must conduct more examinations because present electroanalytical methods cannot reliably predict industrial nanoelectrode performance improvements. Kinetic parameters such as diffusion coefficient, concentration gradient, exchange current density, transport coefficient, and diffusion layer thickness were also analyzed.