From seawater to hydrogen via direct photocatalytic vapor splitting: A review on device design and system integration

Abstract

Solar-driven hydrogen production from seawater attracts great interest for its emerging role in decarbonizing global energy consumption. Given the complexity of natural seawater content, photocatalytic vapor splitting offers a low-cost and safe solution, but with a very low solar-to-hydrogen conversion efficiency. With a focus on cutting-edge photothermal–photocatalytic device design and system integration, the recent research advances on vapor splitting from seawater, as well as industrial implementations in the past decades were reviewed. In addition, the design strategies of the key processes were reviewed, including vapor temperature and pressure control during solar thermal vapor generation from seawater, capillary-fed vaporization with salt repellent, and direct photocatalytic vapor splitting for hydrogen production. Moreover, the existing laboratory-scale and industrial-scale systems, and the integration principles and remaining challenges in the future seawater-to-hydrogen technology were discussed.

Graphical abstract

Keywords

seawater / hydrogen / photocatalytic / vapor splitting / solar-driven

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Acknowledgements

This work was supported by the Department of Chemical Engineering at the University of Waterloo, Canada Research Chair Tier I—Zero-Emission Vehicles and Hydrogen Energy Systems (Grant No. 950-232215), and the Natural Sciences and Engineering Research Council of Canada (NSERC), Discovery Grants Program, RGPIN-2020-04149 and RGPIN-2021-02453.

Competing interests

The authors declare that they have no competing interests.

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