Successful large-scale implementation of solar fuel technologies relies on cost, performance, and reliability of materials, devices, and infrastructures. Earth-abundant, low-cost, easily recyclable, and environmentally benign light absorbers are desired for renewable fuel generation technologies, such as solar photoelectrochemical (PEC) water splitting. Hematite is considered an ideal material for PEC oxygen evolution reaction, which is a critical component in the overall water splitting process for hydrogen fuel generation. However, intrinsic and operational limitations have prevented hematite-based PEC devices from reaching their highest theoretical solar-to-hydrogen efficiency of 15%–17%. Literature clearly shows that no single approach can eliminate these limitations. An overall fundamental understanding of the effect of dopant addition as well as their physical locations and functions within the photoelectrode, in both as-synthesized form and under operating conditions, is of critical importance to unleash the tremendous potentials of hematite-based PEC systems. In this short perspective, the concept of effective doping (i.e., increase of charge carrier density) up to the limit of dopant segregation at the grain boundaries to lower the charge recombination is discussed. Based on relevant theoretical and experimental data from the literature on the effects of surface-to-bulk doping as well as dopant segregation at the grain boundaries on hematite photoelectrode performance, we discuss here the views on the necessity of understanding these processes and their individual and synergistic effects to unravel a simple yet powerful approach to design and develop highly efficient hematite photoanodes for clean hydrogen generation using water and sunlight.
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15 November 2021
Perspective|
November 17 2021
On the relevance of understanding and controlling the locations of dopants in hematite photoanodes for low-cost water splitting
Special Collection:
Materials for Renewable Fuels Production
Joao B. Souza Junior
;
Joao B. Souza Junior
a)
1
Brazilian Nanotechnology National Laboratory (LNNANO), Brazilian Center for Research in Energy and Materials (CNPEM)
, Campinas 13083-970, Brazil
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Flavio L. Souza
;
Flavio L. Souza
b)
1
Brazilian Nanotechnology National Laboratory (LNNANO), Brazilian Center for Research in Energy and Materials (CNPEM)
, Campinas 13083-970, Brazil
2
Centro de Ciências Naturais e Humanas (CCNH), Federal University of ABC (UFABC)
, Santo André 09210580, Brazil
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Lionel Vayssieres
;
Lionel Vayssieres
c)
3
International Research Center for Renewable Energy (IRCRE), State Key Laboratory of Multiphase Flow in Power Engineering, School of Energy and Power Engineering, Xi'an Jiaotong University
, Xi'an 710049, China
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Oomman K. Varghese
Oomman K. Varghese
d)
4
Nanomaterials and Devices Laboratory, Department of Physics, University of Houston
, Houston, Texas 77204, USA
d)Author to whom correspondence should be addressed: [email protected]
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d)Author to whom correspondence should be addressed: [email protected]
Appl. Phys. Lett. 119, 200501 (2021)
Article history
Received:
August 13 2021
Accepted:
November 01 2021
Citation
Joao B. Souza Junior, Flavio L. Souza, Lionel Vayssieres, Oomman K. Varghese; On the relevance of understanding and controlling the locations of dopants in hematite photoanodes for low-cost water splitting. Appl. Phys. Lett. 15 November 2021; 119 (20): 200501. https://doi.org/10.1063/5.0066931
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