Review on Advancements in Catalyst Development for Hydrogen Generation and Fuel Cells: Strategies, Challenges, and Future Prospects

In 2024, global energy consumption reached 592 exajoules (EJ), with a 2% increase from previous year. Along with energy demand, fossil fuels remained dominant at 86.6%, which is concerning due to their energy-related emissions of over 40 Gt CO 2 . These trends, along with rising demand and geopolitical concerns, essential for development of sustainable alternatives. In contrast, Hydrogen shows promising option due to its high energy density (∼120 MJ kg −1 ) and its use in fuel cell vehicles, emit water vapor as byproduct. We reviewed current developments in electrocatalysis for water splitting and fuel cells, and examined their prospects to support development of large-scale “green hydrogen”. We gathered performance of over 100 catalysts, including precious-metals, transition-metal chalcogenides, nitrides, carbides, phosphides, intermetallics, 2D materials such as MXenes, and heteroatom-doped carbons. We examined key electrocatalytic metrics, including overpotential, Tafel slope, exchange current density, hydrogen adsorption free energy, d -band center, density of states, work function, Faradaic efficiency, and stability. Survey indicates that precious-metal catalysts continue to excel in terms of overpotentials and durability. However, non-precious alternatives are approaching state-of-the-art catalysts through compositional tuning and nanostructuring. Our review provides rich-data and mechanistic foundation for next-generation catalysts, also identifying research gaps for hydrogen-powered energy technologies.