Green hydrogen production by water electrolysis: Current status and challenges

The scientific and industrial communities worldwide have recently achieved impressive technical advances in developing innovative electrocatalysts and electrolysers for water and seawater splitting. The viability of water electrolysis for commercial applications, however, remains elusive, and the key barriers are durability, cost, performance, materials, manufacturing, and system simplicity, especially with regard to running on practical water sources like seawater. This paper, therefore, primarily aims to provide a concise overview of the most recent disruptive water-splitting technologies and materials that could reshape the future of green hydrogen production. Starting from water electrolysis fundamentals, the recent advances in developing durable and efficient electrocatalysts for modern types of electrolysers, such as decoupled electrolysers, seawater electrolysers, and unconventional hybrid electrolysers, have been represented and precisely annotated in this report. Outlining the most recent advances in water and seawater splitting, the paper can help as a quick guide in identifying the gap in knowledge for modern water electrolysers while pointing out recent solutions for cost-effective and efficient hydrogen production to meet zero-carbon targets in the short to near term.