Unconventional Water Splitting Platforms

Renewable hydrogen has the potential to reshape our fossil fuel based energy infrastructure as it would allow the integration of a larger share of clean energy sources. Electrolysis of water is one of the most promising pathways toward clean hydrogen production. Although high efficiency electrolyzers are commercially available, their high cost has been a major obstacle for their large scale deployment.

Design simplifications of these devices are necessary in order for clean hydrogen fuel to be deployed. Here, we demonstrate two proof-of-concept devices for water splitting which differ significantly from their conventional counterparts. The first one is a membrane-less electrolyzer which by balancing fluid mechanic forces manages to keep the produced oxygen and hydrogen gas streams separated as shown in Figure 1. This allows the system to operate without commonly required ion conductive membranes, and in this way could reduce the electrolyzer’s cost and enhance its efficiency. 

The second device absorbs water from humid ambient air streams in a Nafion thin-film as demonstrated in Figure 2. The absorbed water molecules split into hydrogen and oxygen streams which are later collected at independent collection ports. The design simplicity of this system makes it appropriate for solar powered hydrogen production since integration of photoactive components can be easily implemented.

Currently, integration of photoelectrodes into these devices is underway. Large scale implementation of the membrane-less device is another ongoing effort.

References

[1] Hashemi, S. Mohammad H., Miguel A. Modestino, and Demetri Psaltis. "A membrane-less electrolyzer for hydrogen production across the pH scale." Energy & Environmental Science (2015).

[2] Modestino, Miguel Antonio, et al. "Vapor-fed microfluidic hydrogen generator." Lab on a Chip (2015).