A short review on generation of green fuel hydrogen through water splitting

Hydrogen is considered as a promising clean and renewable energy carrier and an attractive alternative to fossil fuels. A potential and cheapest way to produce hydrogen is involving water splitting either by light or electricity. The vital step involved in water splitting is the hydrogen evolution reaction (HER) which requires the use of an efficient catalyst to lower its large overpotential value. Therefore, the development of earth-abundant photocatalysts and electrocatalysts with high activity and long-term stability for hydrogen generation gains major attention. The present review summarizes the mechanism of hydrogen production via water splitting utilizing different metal-based and metal-free photocatalysts and electrocatalysts. Different strategies adopted to improve the catalytic activity of electrocatalysts and photocatalysts for water splitting are discussed. Finally, the challenges and future scope of hydrogen evolution reaction are briefly summarized.