Recent advances and future research directions in polyoxometalate-based water electrolysis for hydrogen production

Hydrogen energy, as a clean, efficient, and renewable secondary energy source, serves as a pivotal medium for global energy transition and the attainment of “dual carbon” objectives. Among the various production methods, water electrolysis has emerged as the paramount route for generating green hydrogen, owing to its operational zero carbon emissions and the highly purified hydrogen it produces. However, conventional electrolysis techniques rely heavily on noble metal catalysts, such as platinum and iridium oxide, whose prohibitive cost and limited availability significantly impede their widespread industrial application. Consequently, developing high-performance, stable, and cost-effective catalysts for water electrolysis remains a central challenge in advancing the hydrogen energy sector. Polyoxometalates (POMs), a class of nanoscale metal-oxygen clusters composed of transition metals like molybdenum and tungsten, present a promising alternative due to their diverse redox states, molecular-level tunability, pronounced negative charge, and robust structural stability. This review elucidates the advantages of polyoxometalate-based materials for both the hydrogen evolution reaction (HER) and the oxygen evolution reaction (OER) in water electrolysis. By integrating recent findings, it outlines multiple strategies to overcome current limitations associated with polyoxometalate electrocatalysts. Finally, the discussion addresses the benefits and challenges of employing POM compounds to enhance water electrolysis performance for hydrogen production and, by synthesizing cutting-edge research directions, forecasts future trends in this burgeoning field.