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Efficient solar water-splitting using a nanocrystalline CoO photocatalyst

Nature Nanotechnology volume 9, pages 69–73 (2014)Cite this article

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Abstract

The generation of hydrogen from water using sunlight could potentially form the basis of a clean and renewable source of energy. Various water-splitting methods have been investigated previously1,2,3,4,5,6,7,8, but the use of photocatalysts to split water into stoichiometric amounts of H2 and O2 (overall water splitting) without the use of external bias or sacrificial reagents is of particular interest because of its simplicity and potential low cost of operation1,2,3,4. However, despite progress in the past decade, semiconductor water-splitting photocatalysts (such as (Ga1−xZnx)(N1−xOx)) do not exhibit good activity beyond 440 nm (refs 1,2,9) and water-splitting devices that can harvest visible light typically have a low solar-to-hydrogen efficiency of around 0.1%6,7. Here we show that cobalt(II) oxide (CoO) nanoparticles can carry out overall water splitting with a solar-to-hydrogen efficiency of around 5%. The photocatalysts were synthesized from non-active CoO micropowders using two distinct methods (femtosecond laser ablation and mechanical ball milling), and the CoO nanoparticles that result can decompose pure water under visible-light irradiation without any co-catalysts or sacrificial reagents. Using electrochemical impedance spectroscopy, we show that the high photocatalytic activity of the nanoparticles arises from a significant shift in the position of the band edge of the material.

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Figure 1: Structural and chemical characterizations of CoO nanoparticles.
Figure 2: Characterizations of hydrogen and oxygen evolutions with gas chromatography and mass spectrometry.
Figure 3: Bandgaps and band-edge positions of CoO nanoparticles and micropowders.

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References

  1. Chen, X. B., Shen, S. H., Guo, L. J. & Mao, S. S. Semiconductor-based photocatalytic hydrogen generation. Chem. Rev. 110, 6503–6570 (2010).

    Article  Google Scholar 

  2. Kudo, A. & Miseki, Y. Heterogeneous photocatalyst materials for water splitting. Chem. Soc. Rev. 38, 253–278 (2009).

    Article  Google Scholar 

  3. Osterloh, F. E. & Parkinson, B. A. Recent developments in solar water-splitting photocatalysis. Mater. Res. Soc. Bull. 36, 17–22 (2011).

    Article  Google Scholar 

  4. Mallouk, T. E. The emerging technology of solar fuels. J. Phys. Chem. Lett. 1, 2738–2739 (2010).

    Article  Google Scholar 

  5. Walter, M. G. et al. Solar water splitting cells. Chem. Rev. 110, 6446–6473 (2010).

    Article  Google Scholar 

  6. Mubeen, S. et al. An autonomous photosynthetic device in which all charge carriers derive from surface plasmons. Nature Nanotech. 8, 247–251 (2013).

    Article  Google Scholar 

  7. Liu, C., Tang, J., Chen, H. M., Liu, B. & Yang, P. A fully integrated nanosystem of semiconductor nanowires for direct solar water splitting. Nano Lett. 13, 2989–2992 (2013).

    Article  Google Scholar 

  8. Nocera, D. G. The artificial leaf. Acc. Chem. Res. 45, 767–776 (2012).

    Article  Google Scholar 

  9. Maeda, K., Teramura, K. & Domen, K. Effect of post-calcination on photocatalytic activity of (Ga1–xZnx)(N1–xOx) solid solution for overall water splitting under visible light. J. Catal. 254, 198–204 (2008).

    Article  Google Scholar 

  10. Shi, H. G. & He, X. M. Large-scale synthesis and magnetic properties of cubic CoO nanoparticles. J. Phys. Chem. Solids 73, 646–650 (2012).

    Article  Google Scholar 

  11. Yin, J. S. & Wang, Z. L. Ordered self-assembling of tetrahedral oxide nanocrystals. Phys. Rev. Lett. 79, 2570–2573 (1997).

    Article  Google Scholar 

  12. Yang, H. M., Ouyang, J. & Tang, A. D. Single step synthesis of high-purity CoO nanocrystals. J. Phys. Chem. B 111, 8006–8013 (2007).

    Article  Google Scholar 

  13. Barreca, D. et al. Controlled vapor-phase synthesis of cobalt oxide nanomaterials with tuned composition and spatial organization. CrystEngComm 12, 2185–2197 (2010).

    Article  Google Scholar 

  14. Gallant, D., Pezolet, M. & Simard, S. Optical and physical properties of cobalt oxide films electrogenerated in bicarbonate aqueous media. J. Phys. Chem. B 110, 6871–6880 (2006).

    Article  Google Scholar 

  15. Grimblot, J., Bonnelle, J. P. & Beaufils, J. P. ESCA study on cobalt and molybdenum deposited on alumina – quantitative-analysis of recovery and states of specific cation adsorption. J. Electron Spectrosc. Relat. Phenom. 8, 437–447 (1976).

    Article  Google Scholar 

  16. Amirav, L. & Alivisatos, A. P. Photocatalytic hydrogen production with tunable nanorod heterostructures. J. Phys. Chem. Lett. 1, 1051–1054 (2010).

    Article  Google Scholar 

  17. Xu, Y. & Schoonen, M. A. A. The absolute energy positions of conduction and valence bands of selected semiconducting minerals. Am. Miner. 85, 543–556 (2000).

    Article  Google Scholar 

  18. Vayssieres, L. et al. One-dimensional quantum-confinement effect in α-Fe2O3 ultrafine nanorod arrays. Adv. Mater. 17, 2320–2323 (2005).

    Article  Google Scholar 

  19. Wang, H. L. & Turner, J. A. Characterization of hematite thin films for photoelectrochemical water splitting in a dual photoelectrode device. J. Electrochem. Soc. 157, F173–F178 (2010).

    Article  Google Scholar 

  20. Markus, T. Z. et al. Electronic structure of CdSe nanoparticles adsorbed on Au electrodes by an organic linker: Fermi level pinning of the HOMO. J. Phys. Chem. C 113, 14200–14206 (2009).

    Article  Google Scholar 

  21. Frame, F. A. et al. First demonstration of CdSe as a photocatalyst for hydrogen evolution from water under UV and visible light. Chem. Commun. 2206–2208 (2008).

  22. McCarthy, T. J., Tanzer, T. A. & Kanatzidis, M. G. A new metastable 3-dimensional bismuth sulfide with large tunnels – synthesis, structural characterization, ion-exchange properties, and reactivity of KBi3S5 . J. Am. Chem. Soc. 117, 1294–1301 (1995).

    Article  Google Scholar 

  23. Ishikawa, A. et al. Oxysulfide Sm2Ti2S2O5 as a stable photocatalyst for water oxidation and reduction under visible light irradiation (λ ≤ 650 nm). J. Am. Chem. Soc. 124, 13547–13553 (2002).

    Article  Google Scholar 

  24. Mane, A. U. & Shivashankar, S. A. MOCVD of cobalt oxide thin films: dependence of growth, microstructure, and optical properties on the source of oxidation. J. Cryst. Growth 254, 368–377 (2003).

    Article  Google Scholar 

  25. Holmes, M. A., Townsend, T. K. & Osterloh, F. E. Quantum confinement controlled photocatalytic water splitting by suspended CdSe nanocrystals. Chem. Commun. 48, 371–373 (2012).

    Article  Google Scholar 

  26. Johnson, C. A. et al. Visible-light photoconductivity of Zn1–xCoxO and its dependence on Co2+ concentration. Phys. Rev. B 84, 125203 (2011).

    Article  Google Scholar 

  27. Jasieniak, J., Califano, M. & Watkins, S. E. Size-dependent valence and conduction band-edge energies of semiconductor nanocrystals. ACS Nano 5, 5888–5902 (2011).

    Article  Google Scholar 

  28. Pinaud, B. A., Chen, Z. B., Abram, D. N. & Jaramillo, T. F. Thin films of sodium birnessite-type MnO2: optical properties, electronic band structure, and solar photoelectrochemistry. J. Phys. Chem. C 115, 11830–11838 (2011).

    Article  Google Scholar 

  29. Matsumoto, Y. Energy positions of oxide semiconductors and photocatalysis with iron complex oxides. J. Solid State Chem. 126, 227–234 (1996).

    Article  Google Scholar 

  30. Riha, S. C. et al. Atomic layer deposition of a submonolayer catalyst for the enhanced photoelectrochemical performance of water oxidation with hematite. ACS Nano 7, 2396–2405 (2013).

    Article  Google Scholar 

  31. Marinescu, S. C., Winkler, J. R. & Gray, H. B. Molecular mechanisms of cobalt-catalyzed hydrogen evolution. Proc. Natl Acad. Sci. USA 109, 15127–15131 (2012).

    Article  Google Scholar 

  32. Jiao, F. & Frei, H. Nanostructured cobalt oxide clusters in mesoporous silica as efficient oxygen-evolving catalysts. Angew. Chem. Int. Ed. 48, 1841–1844 (2009).

    Article  Google Scholar 

Download references

Acknowledgements

Financial support from the Robert A. Welch Foundation (E-1728), National Science Foundation (DMR 0907336) and Department of Energy (DE-FG02-13ER46917) is acknowledged. We thank J. Shan and P. Tian for assistance with the purchase of the femtosecond laser, M. Shen, J. Deng, R. Thummel, R. Zhong, H. Fang, Z. Tang, D. Achey, X. Ni, J. Sun, X. Ren, Y. Qi, S Pei, J. Zhao, P. Ruchhoeft, Q. Zhang and J. Allen for help and valuable discussions, and Z. Liu, X. Gong, P. Peng, P. Zhu and M. Fang for various contributions.

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Authors and Affiliations

  1. Department of Electrical & Computer Engineering, University of Houston, Houston, 77204, Texas, USA

    Longb Liao, Qiuhui Zhang, Zhihua Su, Yanan Wang, Yang Li, Xiaoxiang Lu & Jiming Bao

  2. College of Electronics & Information Engineering, Sichuan University, Chengdu, 610064, China

    Qiuhui Zhang & Guoying Feng

  3. Materials Engineering Program, University of Houston, Houston, 77204, Texas, USA

    Zhongzheng Zhao & Jiming Bao

  4. Carl Zeiss Microscopy, LLC, One Zeiss Drive, Thornwood, New York, 10594, USA

    Dongguang Wei

  5. Ingram School of Engineering, and Materials Science, Engineering and Commercialization, Texas State University, San Marcos, TX 78666, USA

    Qingkai Yu

  6. Department of Chemistry, University of Houston, Houston, 77204, Texas, USA

    Xiaojun Cai, Steven Baldelli & Jiming Bao

  7. Institute of Physics, Chinese Academy of Sciences, Beijing, 100190, China

    Jimin Zhao

  8. Department of Physics, University of Houston, Houston, 77204, Texas, USA

    Zhifeng Ren

  9. Department of Physics, Sam Houston State University, Huntsville, 77341, Texas, USA

    Hui Fang

  10. College of Engineering Technology, University of Houston, Houston, 77204, Texas, USA

    Francisco Robles-Hernandez

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  1. Longb Liao
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Contributions

L.L. and J.M.B. conceived, designed and performed the experiments, and analysed the data. D.W. and F.R-H. performed TEM studies, Q.Z. and Y.L. performed ultraviolet–visible measurements, S.B. and X.C. helped design and fabricate reaction chambers, and assisted in electrochemical studies, Q.Y, J.Z. and G.F. assisted in laser ablation, Z.R. and H.F. assisted in ball-milling synthesis, Z.S., Z.Z., Y.W. and X.L. assisted in mass spectrometry, gas chromatography, SEM studies and the solar-simulator set-up, J.M.B. wrote the manuscript and prepared the figures. All authors discussed the results and commented on the manuscript. J.M.B. supervised the project.

Corresponding author

Correspondence to Jiming Bao.

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Liao, L., Zhang, Q., Su, Z. et al. Efficient solar water-splitting using a nanocrystalline CoO photocatalyst. Nature Nanotech 9, 69–73 (2014). https://doi.org/10.1038/nnano.2013.272

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