Efficient solar hydrogen generation in microgravity environment
Abstract
Long-term space missions require extra-terrestrial production of storable, renewable energy. Hydrogen is ascribed a crucial role for transportation, electrical power and oxygen generation. We demonstrate in a series of drop tower experiments that efficient direct hydrogen production can be realized photoelectrochemically in microgravity environment, providing an alternative route to existing life support technologies for space travel. The photoelectrochemical cell consists of an integrated catalyst-functionalized semiconductor system that generates hydrogen with current densities >15 mA/cm^2 in the absence of buoyancy. Conditions are described adverting the resulting formation of ion transport blocking froth layers on the photoelectrodes. The current limiting factors were overcome by controlling the micro- and nanotopography of the Rh electrocatalyst using shadow nanosphere lithography. The behaviour of the applied system in terrestrial and microgravity environment is simulated using a kinetic transport model. Differences observed for varied catalyst topography are elucidated, enabling future photoelectrode designs for use in reduced gravity environments.
Additional Information
© The Author(s) 2018. This article is licensed under a Creative Commons Attribution 4.0 International License, which permits use, sharing, adaptation, distribution and reproduction in any medium or format, as long as you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons license, and indicate if changes were made. The images or other third party material in this article are included in the article's Creative Commons license, unless indicated otherwise in a credit line to the material. If material is not included in the article's Creative Commons license and your intended use is not permitted by statutory regulation or exceeds the permitted use, you will need to obtain permission directly from the copyright holder. To view a copy of this license, visit http://creativecommons.org/licenses/by/4.0/. Received 07 March 2018; Accepted 23 May 2018; Published 10 July 2018. K.B. acknowledges funding from the fellowship programme of the German National Academy of Sciences Leopoldina, grant LPDS 2016-06 and the European Space Agency. Furthermore, she would like to thank Dr. Leopold Summerer, the Advanced Concepts Team, Alan Dowson, Dr. Jack van Loon, Dr. Gabor Milassin, Marcel van Slogteren and Dr. Robert Lindner (ESTEC), Robbert-Jan Noordam (Notese) and Prof. Harry B. Gray (Caltech) for their great support. M.H.R. is grateful for generous support from Prof. Nathan S. Lewis (Caltech). K.B. and M.H.R. acknowledge support from the Beckman Institute of the California Institute of Technology and the Molecular Materials Research Center. M.G. acknowledges funding from the Guangdong Innovative and Entrepreneurial Team Program titled 'Plasmonic Nanomaterials and Quantum Dots for Light Management in Optoelectronic Devices' (No. 2016ZT06C517). Furthermore, the author team greatly acknowledges the effort and support from the ZARM Team with Dr. Thorben Könemann and Dr. Martin Castillo at the Bremen Drop Tower. It is also thankful for enlightening discussions with Prof. Yasuhiro Fukunaka (Waseda University), Prof. Hisayoshi Matsushima (Hokkaido University) and Dr. Slobodan Mitrovic (Lam Research). The team would also like to thank Dr. Eser Metin Akinoglu from the International Academy of Optoelectronics, Zhaoqing, for his help with the SEM characterization of the samples and Dr. Axel Knop-Gericke (Fritz Haber Institute of the Max Planck Society) for his generous help with XPS measurements. Author Contributions: K.B., M.H.R., J.L. and H.-J.L. planned and carried out the terrestrial experiments and the experiments at the Bremen Drop Tower. Ö.A., K.B. and J.L. prepared the nanostructured photoelectrodes under the supervision of M.G. and H.-J.L. K.T.F. carried out the theoretical calculations and simulations. K.B., H.-J.L and K.T.F. wrote the manuscript which is approved by all authors. The authors declare no competing interests. Data availability: All relevant data are available from the authors upon request.Attached Files
Published - s41467-018-04844-y.pdf
Supplemental Material - 41467_2018_4844_MOESM1_ESM.pdf
Supplemental Material - 41467_2018_4844_MOESM2_ESM.pdf
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Additional details
- PMCID
- PMC6039473
- Eprint ID
- 87681
- Resolver ID
- CaltechAUTHORS:20180710-080707049
- LPDS 2016-06
- Deutsche Akademie der Naturforscher Leopoldina
- European Space Agency (ESA)
- Caltech Beckman Institute
- 2016ZT06C517
- Guangdong Innovative and Entrepreneurial Team Program
- Created
-
2018-07-10Created from EPrint's datestamp field
- Updated
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2022-03-09Created from EPrint's last_modified field
- Caltech groups
- JCAP, Resnick Sustainability Institute