Saad Uddin Mahmud, Yew Heng Teoh, Heoy Geok How, Haseeb Yaqoob, Mohamad Yusof Idroas, Thanh Danh Le, Muhammad Ahmad Jamil, Hafiz Muhammad Ali, Muhammad Wakil Shahzad
Hydrogen was proposed as an alternative fuel in 1968, marking the start of its journey toward becoming a sustainable energy source. Although several methods exist for producing green hydrogen, water electrolysis remains the most promising because it is compatible with renewable energy and can produce high-purity hydrogen without carbon emissions. In this review, we propose a comparative framework linking catalyst durability, operating conditions, and LCOH to technology readiness. Our findings show that improved catalysts, better electrolyzer designs, and tighter integration with renewable energy have all contributed to higher efficiency and greater durability. However, high energy use, material degradation, and challenges in large-scale production are major obstacles to the widespread use of green hydrogen. This highlights the need for focused research to develop sustainable, cost-effective production methods. Overall, this review offers practical guidance for improving catalyst performance and advancing more efficient, durable, and scalable green hydrogen systems for future applications.