Abstract
Hydrogen production from water electrolysis is one of the most promising approaches for the production of green H2, a fundamental asset for the decarbonization of the energy cycle and industrial processes. Seawater is the most abundant water source on Earth, and it should be the feedstock for these new technologies. However, commercial electrolyzers still need ultrapure water. The debate over the advantages and disadvantages of direct sea water electrolysis when compared with the implementation of a distillation/purification process before the electrolysis stage is building in the relevant research. However, this debate will remain open for some time, essentially because there are no seawater electrolyser technologies with which to compare the modular approach. In this study, we attempted to build and validate an autonomous sea water electrolyzer able to produce high-purity green hydrogen (>90%) from seawater. We were able to solve most of the problems that natural seawater electrolyses imposes (high corrosion, impurities, etc.), with decisions based on simplicity and sustainability, and those issues that are yet to be overcome were rationally discussed in view of future electrolyzer designs. Even though the performance we achieved may still be far from industrial standards, our results demonstrate that direct seawater electrolysis with a solar-to-hydrogen efficiency of ≈7% can be achieved with common, low-cost materials and affordable fabrication methods.
Highlights
IntroductionWater is an environmentally clean hydrogen source
Our first task was the synthesis of the CoFe-Prussian blue derivatives (PBs) nanoparticles, which had an average particle size around 70 nm, as confirmed by transmission electron microscopy (TEM)
Our first task was the synthesis of the CoFe-PB nanoparticles, which had an average particle size around 70 nm, as confirmed by TEM (Figure S1a in Section S1 in Supplementary Materials) and by dynamic light scattering (DLS) (Figure S1b), while it was above 200 nm in a similar synthesis procedure in which the aqueous solutions of Co-Fe precursors were used [17]
Summary
Water is an environmentally clean hydrogen source. The electrochemical conversion of water into hydrogen and oxygen through a water electrolysis process appears to be the most promising method to produce high-quality green hydrogen on both large and domestic scales. Water is abundant on earth, pure water is scarce because 97.5% of water is salty and only 2.5% is fresh. 80% of fresh water is frozen in the icecaps or combined as soil moisture [1]. Considering that fresh water is vital for human life and that there are major access problems in large parts of the world [2], the advantage of using salty water sources as feedstock for hydrogen production seems obvious
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
