Abstract
Hydrogen (H2) stands as the leading alternative to fossil fuels due to its renewable nature, exceptional energy-carrying capacity, and zero carbon dioxide emissions. Researchers increasingly favor large-scale H2 production via water electrolysis powered by renewable energy, with water splitting being a viable method for long-term, sustainable energy storage. Noble metals efficiently catalyze the hydrogen evolution reaction (HER), but the performance of water electrolysis largely depends on the activity of the electrocatalysts. To further advance renewable energy technology, researchers are developing highly efficient, stable, cost-effective, and less toxic catalysts like CuO, NiO, Co3O4, FeP/FeP2, CoP/Co2P, MoP, and NiCo2O4. Single-atom catalysts (SACs) have gained significant attention for their exceptional catalytic activity and high atom-utilization efficiency. Atomic Layer Deposition (ALD) has become one of the most effective methods for fabricating SACs due to its precise ability to deposit small atoms uniformly. This paper explores the recent advancements in SAC synthesis for HER, focusing on the ALD technique to enhance catalytic efficiency and performance.