Perspective on direct seawater electrolysis and electrodesalination: innovations and future directions for mining green X

Abstract

Molecular hydrogen (H2) represents a sustainable and environmentally benign energy resource. Of the various methodologies that have been developed for H2 production, water electrolysis has garnered particular attention due to its ability to generate H2 without emitting CO2 or other pollutants, with seawater electrolysis receiving significant focus due to the abundance and accessibility of seawater. However, both direct and indirect seawater electrolysis technologies have a number of practical limitations, including the high energy consumption and maintenance costs associated with seawater desalination systems and the need for strong alkaline conditions. Nevertheless, indirect seawater electrolysis, which amalgamates desalination and water electrolysis processes by employing clean water produced by seawater reverse osmosis (RO) as the feed for water splitting, is currently considered more economical than direct electrolysis. Electrodeionization has also emerged as an alternative to conventional seawater RO due to its high energy efficiency and environmental advantages. In addition, the development of environmentally friendly processes to simultaneously extract high-value compounds from seawater and the brine produced as a by-product from seawater RO can mitigate the high process costs associat