Effect of Choline Proline Ionic Liquid Additives on Hydrogen Evolution in Alkaline Water Electrolysis

Conventional hydrogen generation mostly depends on steam methane reforming (SMR), thereby contributing to greenhouse gas emissions. Alkaline water electrolysis using KOH is a promising method for green hydrogen production, but faces significant technical challenges such as high energy consumption and lower hydrogen production. Despite extensive research on various electrolyte modifications, a significant gap exists in the application of biodegradable and biocompatible amino acid-based ionic liquids as electrolyte additives. This study used a modified Hofman cell reaction setup for performing water electrolysis experiments. The selected ionic liquid (IL) was synthesized, and its chemical structure and purity were characterized by FT-IR and H NMR spectroscopy. Subsequently, comprehensive electrochemical analyses, including linear sweep voltammetry, electrochemical impedance spectroscopy, Tafel analysis, and chronoamperometry, were conducted to investigate the electrochemical behavior of the system. The electrochemical analyses were conducted using a three-electrode setup in a 1 M KOH solution with 0 to 4 vol % choline proline [Cho]-[Pro] as an additive. Consequently, the decrease in charge transfer resistance (R _ct) was observed from 36.1 to 20.5 kΩ during electrochemical impedance spectroscopy. Moreover, the incorporation of [Cho]-[Pro] increases hydrogen production by 1.6-fold and reduces power consumption by 1.3-fold compared to pure 1 M KOH. The findings demonstrate that amino acid-based ionic liquids can significantly enhance the efficiency and sustainability of alkaline water electrolysis, thereby promoting the transition to sustainable energy systems and reducing dependence on fossil fuels.