Background: The transition to a low-carbon energy system is a global priority to mitigate climate change. Green hydrogen, produced from renewable sources, has emerged as a promising clean energy carrier with the potential to decarbonize various sectors of the economy. This comprehensive review synthesizes the current state of green hydrogen production technologies, highlighting the associated challenges, research trends, and future directions.

Methods: A systematic literature review was conducted using a predefined search strategy, resulting in the selection of 121 peer-reviewed articles and reports. The selected literature was thematically analyzed to identify and categorize the key technologies, challenges, and future prospects of green hydrogen production.

Results: The review provides a detailed analysis of the two primary pathways for green hydrogen production: water electrolysis and biomass conversion. For water electrolysis, we discuss four key technologies: Alkaline Water Electrolysis (AWE), Proton Exchange Membrane (PEM) electrolysis, Anion Exchange Membrane (AEM) electrolysis, and Solid Oxide Electrolysis (SOE). For biomass-based production, we examine the processes of pyrolysis and gasification. The principles, advantages, and limitations of each technology are discussed in detail.

Conclusion: While significant progress has been made in green hydrogen production technologies, several challenges remain, including cost competitiveness, infrastructure development, and water resource management. Future research should focus on developing advanced materials for electrolyzers, improving the integration of electrolysis with renewable energy sources, and establishing supportive policy frameworks. Overcoming these challenges will be crucial for unlocking the full potential of green hydrogen and accelerating the transition to a sustainable energy future.