Recent Developments on Water Electrolyzers for Hydrogen Production: A Technological Review

Rapid fossil fuel declination has positioned hydrogen as a promising alternative fuel capable of meeting global energy demand while offering zero greenhouse gas (GHG) emissions. Traditionally, hydrogen was primarily produced from natural gas, resulting in significant GHG emissions, with distinctions only in labeling as gray or blue hydrogen. Recently, green hydrogen using renewable energy sources has gained considerable scientific interest. Among the available technologies, alkaline water electrolysis (AWE) remains the most mature and stable, with recent advances in cost‐effective catalysis. Significant progress has been made in polymer electrolyte membrane (PEM) technology. Additionally, research focus has expanded to include high‐purity hydrogen production using solid oxide electrolysis cells (SOECs) and simultaneous wastewater treatment via microbial electrolysis cells (MECs). This review presents the current technological status, recent advancements, and factors influencing operational efficiency, along with a structured quantitative comparison of AWE, PEM, and SOEC technologies based on efficiency, energy consumption, and techno‐economic indicators.