Hostname: page-component-78c5997874-mlc7c Total loading time: 0 Render date: 2024-11-19T18:47:25.015Z Has data issue: false hasContentIssue false

Toward efficient solar water splitting over hematite photoelectrodes

Published online by Cambridge University Press:  07 November 2013

Shaohua Shen*
Affiliation:
International Research Center for Renewable Energy, State Key Laboratory of Multiphase Flow in Power Engineering, Xi'an Jiaotong University, Shaanxi 710049, China
*
a)Address all correspondence to this author. e-mail: shshen_xjtu@mail.xjtu.edu.cn
Get access

Abstract

Hematite has been considered as one of the most promising materials for solar water splitting, although its photoelectrochemical performance is still not very high and limited by its intrinsic properties. In the past few years, sizable advances in the development of hematite photoelectrodes for enhanced water splitting activities have been achieved by a variety of rational modification strategies, including nanostructure design for efficient charge collection, metal ion doping for promoted charge carrier transfer, heterojunctions for efficient charge separation, and surface and/or interface modification for retarded charge recombination and enhanced light absorption. In this article, research work and milestone achievement actually focused on hematite photoelectrodes for water splitting is reviewed in detail. A review on this topic by answering the key question, “how to modify or design hematite photoelectrode to improve its conductivity, enhance charge separation as well as catalyze surface water oxidation,” in authors' view, can be potentially helpful to enable hematite for further efficient solar energy conversion, which will be very inspiring and important to this field.

Type
Reviews
Copyright
Copyright © Materials Research Society 2013 

Access options

Get access to the full version of this content by using one of the access options below. (Log in options will check for institutional or personal access. Content may require purchase if you do not have access.)

References

REFERENCES

Fujishima, A. and Honda, K.: Electrochemical photolysis of water at a semiconductor electrode. Nature 238, 37 (1972).Google Scholar
Chen, X., Shen, S., Guo, L., and Mao, S.S.: Semiconductor-based photocatalytic hydrogen generation. Chem. Rev. 110, 6503 (2010).CrossRefGoogle ScholarPubMed
Shen, S., Shi, J., Guo, P., and Guo, L.: Visible-light-driven photocatalytic water splitting on nanostructured semiconducting materials. Int. J. Nanotechnol. 8, 523 (2011).CrossRefGoogle Scholar
Kudo, A. and Miseki, Y.: Heterogeneous photocatalyst materials for water splitting. Chem. Soc. Rev. 38, 253 (2009).CrossRefGoogle ScholarPubMed
Tong, H., Ouyang, S., Bi, Y., Umezawa, N., Oshikiri, M., and Ye, J.: Nanophotocatalytic materials: Possibilities and challenges. Adv. Mater. 24, 229 (2012).Google Scholar
Shen, S. and Mao, S.S.: Nanostructure designs for effective solar-to-hydrogen conversion. Nanophotonics 1, 31 (2012).Google Scholar
Chen, Z., Jaramillo, T.F., Deutsch, T.G., Kleiman-Shwarsctein, A., Forman, A.J., Gaillard, N., Garland, R., Takanabe, K., Heske, C., Sunkara, M., McFarland, E.W., Domen, K., Miller, E.L., Turner, J.A., and Dinh, H.N.: Accelerating materials development for photoelectrochemical hydrogen production: Standards for methods, definitions, and reporting protocols. J. Mater. Res. 25, 3 (2010).Google Scholar
Brillet, J., Cornuz, M., Le Formal, F., Yum, J-H., Grätzel, M., and Sivula, K.: Examining architectures of photoanode-photovoltaic tandem cells for solar water splitting. J. Mater. Res. 25, 17 (2010).CrossRefGoogle Scholar
Sartoretti, C.J., Ulmann, M., Alexander, B.D., Augustynski, J., and Weidenkaff, A.: Photoelectrochemical oxidation of water at transparent ferric oxide film electrodes. Chem. Phys. Lett. 376, 194 (2003).Google Scholar
Kennedy, J.H. and Frese, J.K.W.: Photooxidation of water at alpha-Fe2O3 electrodes. J. Electrochem. Soc. 125, 709 (1978).Google Scholar
Morin, F.J.: Electrical properties of αFe2O3 and αFe2O3 containing titanium. Phys. Rev. 83, 1005 (1951).CrossRefGoogle Scholar
Morin, F.J.: Electrical properties of α-Fe2O3 . Phys. Rev. 93, 1195 (1954).CrossRefGoogle Scholar
Dare-Edwards, M.P., Goodenough, J.B., Hamnett, A., and Trevellick, P.R.: Electrochemistry and photoelectrochemistry of iron(III) oxide. J. Chem. Soc. Faraday Trans. 79, 2027 (1983).Google Scholar
Sivula, K., Formal, F.L., and Grätzel, M.: Solar water splitting: Progress using hematite (α-Fe2O3) photoelectrodes. ChemSusChem 4, 432 (2011).CrossRefGoogle Scholar
Katz, M.J., Riha, S.C., Jeong, N.C., Martinson, A.B.F., Farha, O.K., and Hupp, J.T.: Toward solar fuels: Water splitting with sunlight and “rust”? Coord. Chem. Rev. 256, 2521 (2012).CrossRefGoogle Scholar
Wheeler, D.A., Wang, G., Ling, Y., Li, Y., and Zhang, J.Z.: Nanostructured hematite: Synthesis, characterization, charge carrier dynamics, and photoelectrochemical properties. Energy Environ. Sci. 5, 6682 (2012).CrossRefGoogle Scholar
Bora, D.K., Braun, A., and Constable, E.C.: “In rust we trust”. Hematite: The prospective inorganic backbone for artificial photosynthesis. Energy Environ. Sci. 6, 407 (2013).Google Scholar
Hamann, T.W.: Splitting water with rust: Hematite photoelectrochemistry. Dalton Trans. 41, 7830 (2012).CrossRefGoogle ScholarPubMed
Cesar, I., Sivula, K., Kay, A., Zboril, R., and Grätzel, M.: Influence of feature size, film thickness, and silicon doping on the performance of nanostructured hematite photoanodes for solar water splitting. J. Phys. Chem. C 113, 772 (2009).CrossRefGoogle Scholar
Vayssieres, L., Beermann, N., Lindquist, S.E., and Hagfeldt, A.: Controlled aqueous chemical growth of oriented three dimensional crystalline nanorod arrays: Application to iron(III) oxides. Chem. Mater. 13, 233 (2001).Google Scholar
Lindgren, T., Wang, H.L., Beermann, N., Vayssieres, L., Hagfeldt, A., and Lindquist, S.E.: Aqueous photoelectrochemistry of hematite nanorod array. Sol. Energy Mater. Sol. Cells 71, 231 (2002).CrossRefGoogle Scholar
de Carvalho, V.A.N., de S. Luz, R.A., Lima, B.H., Crespilho, F.N., Leite, E.R., and Souza, F.L.: Highly oriented hematite nanorods arrays for photoelectrochemical water splitting. J. Power Sources 205, 525 (2012).Google Scholar
Pradhan, G.K. and Parida, K.M.: Fabrication, growth mechanism, and characterization of α-Fe2O3 nanorods. ACS Appl. Mater. Interfaces 3, 317 (2011).Google Scholar
Chernomordik, B.D., Russell, H.B., Cvelbar, U., Jasinski, J.B., Kumar, V., Deutsch, T., and Sunkara, M.K.: Photoelectrochemical activity of as-grown, α-Fe2O3 nanowire array electrodes for water splitting. Nanotechnology 23, 194009 (2012).CrossRefGoogle ScholarPubMed
Grigorescu, S., Lee, C.Y., Lee, K., Albu, S., Paramasivam, I., Demetrescu, I., and Schmuki, P.: Thermal air oxidation of Fe: Rapid hematite nanowire growth and photoelectrochemical water splitting performance. Electrochem. Commun. 23, 59 (2012).CrossRefGoogle Scholar
Chang, C.Y., Wang, C.H., Tseng, C.J., Cheng, K.W., Hourng, L.W., and Tsai, B.T.: Self-oriented iron oxide nanorod array thin film for photoelectrochemical hydrogen production. Int. J. Hydrogen Energy 37, 13616 (2012).Google Scholar
Li, L., Yu, Y., Meng, F., Tan, Y., Hamers, R.J., and Jin, S.: Facile solution synthesis of α-FeF3·3H2O nanowires and their conversion to α-Fe2O3 nanowires for photoelectrochemical application. Nano Lett. 12, 724 (2012).Google Scholar
Mao, A., Shin, K., Kim, J.K., Wang, D., Han, G., and Park, J.H.: Controlled synthesis of vertically aligned hematite on conducting substrate for photoelectrochemical cells: Nanorods versus nanotubes. ACS Appl. Mater. Interfaces 3, 1852 (2011).Google Scholar
Mor, G.K., Prakasam, H.E., Varghese, O.K., Shankar, K., and Grimes, C.A.: Vertically oriented Ti–Fe–O nanotube array films: Toward a useful material architecture for solar spectrum water photoelectrolysis. Nano Lett. 7, 2356 (2007).CrossRefGoogle Scholar
Mor, G.K., Shankar, K., Paulose, M., Varghese, O.K., and Grimes, C.A.: Enhanced photocleavage of water using titania nanotube arrays. Nano Lett. 5, 191 (2007).CrossRefGoogle Scholar
Shankar, K., Mor, G.K., Prakasam, H.E., Yoriya, S., Paulose, M., Varghese, O.K., and Grimes, C.A.: Highly-ordered TiO2 nanotube arrays up to 220 μm in length: Use in water photoelectrolysis and dye-sensitized solar cells. Nanotechnology 18, 065707 (2007).Google Scholar
Paulose, M., Shankar, K., Yoriya, S., Prakasam, H.E., Varghese, O.K., Mor, G.K., Latempa, T.A., Fitzgerald, A., and Grimes, C.A.: Anodic growth of highly ordered TiO2 nanotube arrays to 134 μm in length. J. Phys. Chem. B 110, 16179 (2006).CrossRefGoogle ScholarPubMed
Mor, G.K., Varghese, O.K., Wilke, R.H.T., Sharma, S., Shankar, K., Latempa, T.J., Choi, K.S., and Grimes, C.A.: P-type Cu–Ti–O nanotube arrays and their use in self-biased heterojunction photoelectrochemical diodes for hydrogen generation. Nano Lett. 8, 1906 (2008).Google Scholar
Prakasam, H.E., Varghese, O.K., Paulose, M., Mor, G.K., and Grimes, C.A.: Synthesis and photoelectrochemical properties of nanoporous iron (III) oxide by potentiostatic anodization. Nanotechnology 17, 4285 (2006).Google Scholar
Mohapatra, S.K., John, S.E., Banerjee, S., and Misra, M.: Water photooxidation by smooth and ultrathin α-Fe2O3 nanotube arrays. Chem. Mater. 21, 3048 (2009).Google Scholar
Zhang, Z., Hossain, M.F., and Takahashi, T.: Self-assembled hematite (α-Fe2O3) nanotube arrays for photoelectrocatalytic degradation of azo dye under simulated solar light irradiation. Appl. Catal., B 95, 423 (2010).Google Scholar
Jun, H., Im, B., Kim, J.Y., Im, Y.O, Jang, J.W., Kim, E.S., Kim, J.Y., Kang, H.J., Hong, S.J., and Lee, J.S.: Photoelectrochemical water splitting over ordered honeycomb hematite electrodes stabilized by alumina shielding. Energy Environ. Sci. 5, 6375 (2012).Google Scholar
Rangaraju, R.R., Panday, A., Raja, K.S., and Misra, M.: Nanostructured anodic iron oxide film as photoanode for water oxidation. J. Phys. D: Appl. Phys. 42, 135303 (2009).CrossRefGoogle Scholar
Sivula, K., Zboril, R., Formal, F.L., Robert, R., Weidenkaff, A., Tucek, J., Frydrych, J., and Grätzel, M.: Photoelectrochemical water splitting with mesoporous hematite prepared by a solution-based colloidal approach. J. Am. Chem. Soc. 132, 7436 (2010).Google Scholar
Brillet, J., Grätzel, M., and Sivula, K.: Decoupling feature size and functionality in solution-processed, porous hematite electrodes for solar water splitting. Nano Lett. 10, 4155 (2010).Google Scholar
Gonçalves, R.H., Lima, B.H.R., and Leite, E.R.: Magnetite colloidal nanocrystals: A facile pathway to prepare mesoporous hematite thin films for photoelectrochemical water splitting. J. Am. Chem. Soc. 133, 6012 (2011).Google Scholar
Hamd, W., Cobo, S., Fize, J., Baldinozzi, G., Schwartz, W., Reymermier, M., Pereira, A., Fontecave, M., Artero, V., Robert, C.L., and Sanchez, C.: Mesoporous α-Fe2O3 thin films synthesized via the sol–gel process for light-driven water oxidation. Phys. Chem. Chem. Phys. 14, 13224 (2012).Google Scholar
Wang, L., Lee, C.Y., and Schmuki, P.: Solar water splitting: Preserving the beneficial small feature size in porous α-Fe2O3 photoelectrodes during annealing. J. Mater. Chem. A 1, 212 (2013).Google Scholar
Rahman, G. and Joo, O.S.: Facile preparation of nanostructured α-Fe2O3 thin films with enhanced photoelectrochemical water splitting activity. J. Mater. Chem. A 1, 5554 (2013).CrossRefGoogle Scholar
Vincent, T., Gross, M., Dotan, H., and Rothschild, A.: Thermally oxidized iron oxide nanoarchitectures for hydrogen production by solar-induced water splitting. Int. J. Hydrogen Energy 37, 8102 (2012).Google Scholar
Tamboli, S.H., Rahman, G., and Joo, O.S.: Influence of potential, deposition time and annealing temperature on photoelectrochemical properties of electrodeposited iron oxide thin films. J. Alloys Compd. 520, 232 (2012).Google Scholar
Shinde, P.S., Go, G.H., and Lee, W.J.: Facile growth of hierarchical hematite (α-Fe2O3) nanopetals on FTO by pulse reverse electrodeposition for photoelectrochemical water splitting. J. Mater. Chem. 22, 10469 (2012).Google Scholar
Patil, S.A., Shinde, D.V., Kim, E., Lee, J.K., Mane, R.S., and Han, S.H.: Photoelectrochemistry of solution processed hematite nanoparticles, nanoparticle-chains and nanorods. RSC Adv. 2, 11808 (2012).Google Scholar
Zheng, J.Y., Kang, M.J., Song, G., Son, S.I., Suh, S.P., Kim, C.W., and Kang, Y.S.: Morphology evolution of dendritic Fe wire array by electrodeposition, and photoelectrochemical properties of α-Fe2O3 dendritic wire array. Cryst. Eng. Commun. 14, 6957 (2012).CrossRefGoogle Scholar
Kay, A., Cesar, I., and Grätzel, M.: New benchmark for water photooxidation by nanostructured α-Fe2O3 films. J. Am. Chem. Soc. 128, 15714 (2006).CrossRefGoogle ScholarPubMed
Riha, S.C., Vermeer, M.J.D., Pellin, M.J., Hupp, J.T., and Martinson, A.B.F.: Hematite-based photo-oxidation of water using transparent distributed current collectors. ACS Appl. Mater. Interfaces 5, 360 (2013).Google Scholar
Launay, J.C. and Horowitz, G.: Crystal growth and photoelectrochemical study of Zr-doped α-Fe2O3 single crystal. J. Cryst. Growth 57, 118 (1982).Google Scholar
Cao, D., Luo, W., Li, M., Feng, J., Li, Z., and Zou, Z.: A transparent Ti4+ doped hematite photoanode protectively grown by a facile hydrothermal method. Cryst. Eng. Commun. 15, 2386 (2013).CrossRefGoogle Scholar
Deng, J., Zhong, J., Pu, A., Zhang, D., Li, M., Sun, X., and Lee, S.T.: Ti-doped hematite nanostructures for solar water splitting with high efficiency. J. Appl. Phys. 112, 084312 (2012).Google Scholar
Lian, X., Yang, X., Liu, S., Xu, Y., Jiang, C., Chen, J., and Wang, R.: Enhanced photoelectrochemical performance of Ti-doped hematite thin films prepared by the sol–gel method. Appl. Surf. Sci. 258, 2307 (2012).Google Scholar
Kumari, S., Singh, A.P., Sonal, , Deva, D., Shrivastav, R., Dass, S., and Satsangi, V.R.: Spray pyrolytically deposited nanoporous Ti4+ doped hematite thin films for efficient photoelectrochemical splitting of water. Int. J. Hydrogen Energy 35, 3985 (2010).Google Scholar
Kronawitter, C.X., Mao, S.S., and Antoun, B.R.: Doped, porous iron oxide films and their optical functions and anodic photocurrents for solar water splitting. Appl. Phys. Lett. 98, 092108 (2011).Google Scholar
Zandi, O., Klahr, B.M., and Hamann, T.W.: Highly photoactive Ti-doped α-Fe2O3 thin film electrodes: Resurrection of the dead layer. Energy Environ. Sci. 6, 634 (2013).Google Scholar
Zhang, P., Shwarsctein, A.K., Hu, Y.S., Lefton, J., Sharma, S., Formand, A.J., and McFarland, E.: Oriented Ti doped hematite thin film as active photoanodes synthesized by facile APCVD. Energy Environ. Sci. 4, 1020 (2011).Google Scholar
Wang, G., Ling, Y., Wheeler, D.A., George, K.E.N., Horsley, K., Heske, C., Zhang, J.Z., and Li, Y.: Facile synthesis of highly photoactive r-Fe2O3-based films for water oxidation. Nano Lett. 11, 3503 (2011).CrossRefGoogle ScholarPubMed
Kumar, P., Sharma, P., Shrivastav, R., Dass, S., and Satsangi, V.R.: Electrodeposited zirconium-doped α-Fe2O3thin film for photoelectrochemical water splitting. Int. J. Hydrogen Energy 36, 2777 (2011).Google Scholar
Kumar, P., Sharma, P., Joshi, A.G., Shrivastav, R., Dass, S., and Satsangi, V.R.: Nano porous hematite for solar hydrogen production. J. Electrochem. Soc. 159(8), H685 (2012).Google Scholar
Shwarsctein, A.K., Huda, M.N., Walsh, A., Yan, Y., Stucky, G.D., Hu, Y., Al-Jassim, M.M., and McFarland, E.W.: Electrodeposited aluminum-doped α-Fe2O3 photoelectrodes: Experiment and theory. Chem. Mater. 22, 510 (2010).CrossRefGoogle Scholar
Hu, Y., Shwarsctein, A.K., Forman, A.J., Hazen, D., Park, J.N., and McFarland, E.W.: Pt-doped r-Fe2O3 thin films active for photoelectrochemical water splitting. Chem. Mater. 20, 3803 (2008).Google Scholar
Shwarsctein, A.K., Hu, Y., Forman, A.J., Stucky, G.D., and McFarland, E.W.: Electrodeposition of α-Fe2O3 doped with Mo or Cr as photoanodes for photocatalytic water splitting. J. Phys. Chem. C 112, 15900 (2008).Google Scholar
Yarahmadi, S.S., Wijayantha, K.G.U., Tahir, A.A., and Vaidhyanathan, B.: Nanostructured r-Fe2O3 electrodes for solar driven water splitting: Effect of doping agents on preparation and performance. J. Phys. Chem. C 113, 4768 (2009).Google Scholar
Lukowski, M.A. and Jin, S.: Improved synthesis and electrical properties of Si-doped α-Fe2O3 nanowires. J. Phys. Chem. C 115, 12388 (2011).Google Scholar
Souza, F.L., Lopes, K.P., Nascente, P.A.P., and Leite, E.R.: Nanostructured hematite thin films produced by spin-coating deposition solution: Application in water splitting. Sol. Energy Mater. Sol. Cells 93, 362 (2009).Google Scholar
Chemelewski, W.D., Hahn, N.T., and Mullins, C.B.: Effect of Si doping and porosity on hematite’s (α-Fe2O3) photoelectrochemical water oxidation performance. J. Phys. Chem. C 116, 5255 (2012).Google Scholar
Morrish, R., Rahman, M., MacElroy, J.M.D., and Wolden, C.A.: Activation of hematite nanorod arrays for photoelectrochemical water splitting. ChemSusChem 4, 474 (2011).Google Scholar
Ling, Y., Wang, G., Wheeler, D.A., Zhang, J.Z., and Li, Y.: Sn-doped hematite nanostructures for photoelectrochemical water splitting. Nano Lett. 11, 2119 (2011).CrossRefGoogle ScholarPubMed
Frydrych, J., Machala, L., Tucek, J., Siskova, K., Filip, J., Pechousek, J., Safarova, K., Vondracek, M., Seo, J.H., Schneeweiss, O., Grätzel, M., Sivula, K., and Zboril, R.: Facile fabrication of tin-doped hematite photoelectrodes–effect of doping on magnetic properties and performance for light-induced water splitting. J. Mater. Chem. 22, 23232 (2012).Google Scholar
Meng, X., Qin, G., Goddard, W.A. III, Li, S., Pan, H., Wen, X., Qin, Y., and Zuo, L.: Theoretical understanding of enhanced photoelectrochemical catalytic activity of Sn-doped hematite: Anisotropic catalysis and effects of morin transition and Sn doping. J. Phys. Chem. C 117, 3779 (2013).Google Scholar
Shen, S., Kronawitter, C.X., Jiang, J., Mao, S.S., and Guo, L.: Surface tuning for promoted charge transfer in hematite nanorod arrays as water-splitting photoanodes. Nano Res. 5, 327 (2012).Google Scholar
Aroutiounian, V.M., Arakelyan, V.M., Shahnazaryan, G.E., Stepanyan, G.M., Turner, J.A., and Khaselev, O.: Investigation of ceramic Fe2O3 $\left\langle {{\rm{Ta}}} \right\rangle$ photoelectrodes for solar energy photoelectrochemical converters. Int. J. Hydrogen Energy 27, 33 (2002).Google Scholar
Sanchez, C., Hendewerk, M., Sieber, K.D., and Somorjai, G.A.: Synthesis, bulk, and surface characterization of niobium-doped Fe2O3 single crystals. J. Solid State Chem. 61, 47 (1986).Google Scholar
Miyake, H. and Kozuka, H.: Photoelectrochemical properties of Fe2O3-Nb2O5 films prepared by sol-gel method. J. Phys. Chem. B 109, 17951 (2005).Google Scholar
Liu, J., Liang, C., Xu, G., Tian, Z., Shao, G., and Zhang, L.: Ge-doped hematite nanosheets with tunable doping level, structure and improved photoelectrochemical performance. Nano Energy 2, 328 (2013).Google Scholar
Liu, Y., Yu, Y., and Zhang, W.: Photoelectrochemical properties of Ni-doped Fe2O3 thin films prepared by electrodeposition. Electrochim. Acta 59, 121 (2012).Google Scholar
Seki, M., Yamahara, H., and Tabata, H.: Enhanced photocurrent in Rh-substituted α-Fe2O3 thin films grown by pulsed laser deposition. Appl. Phys. Exp. 5, 115801 (2012).Google Scholar
Liao, P., Toroker, M.C., and Carter, E.A.: Electron transport in pure and doped hematite. Nano Lett. 11, 1775 (2011).Google Scholar
Ingler, W.B. Jr., Baltrus, J.P. and Khan, S.U.M.: Photoresponse of p-type zinc-doped iron(III) oxide thin films. J. Am. Chem. Soc. 126, 10238 (2004).Google Scholar
Ingler, W.B. Jr. and Khan, S.U.M.: Photoresponse of spray pyrolytically synthesized copper-doped p-Fe2O3 thin film electrodes in water splitting. Int. J. Hydrogen Energy 30, 821 (2005).Google Scholar
Ingler, W.B. Jr. and Khan, S.U.M.: Photoresponse of spray pyrolytically synthesized magnesium-doped iron (III) oxide (p-Fe2O3) thin films under solar simulated light illumination. Thin Solid Films 461, 301 (2004).Google Scholar
Sartoretti, C.J., Alexander, B.D., Solarska, R., Rutkowska, I.A., and Augustynski, J.: Photoelectrochemical oxidation of water at transparent ferric oxide film electrodes. J. Phys. Chem. B 109, 13685 (2005).Google Scholar
Jang, J.S., Lee, J., Ye, H., Fan, F.F., and Bard, A.J.: Rapid screening of effective dopants for Fe2O3 photocatalysts with scanning electrochemical microscopy and investigation of their photoelectrochemical properties. J. Phys. Chem. C 113, 6719 (2009).Google Scholar
Tang, H., Yin, W., Matin, M.A., Wang, H., Deutsch, T., Al-Jassim, M.M., Turner, J.A., and Yan, Y.: Titanium and magnesium Co-alloyed hematite thin films for photoelectrochemical water splitting. J. Appl. Phys. 111, 073502 (2012).CrossRefGoogle Scholar
Spray, R.L., McDonald, K.J., and Choi, K.S.: Enhancing photoresponse of nanoparticulate α-Fe2O3 electrodes by surface composition tuning. J. Phys. Chem. C 115, 3497 (2011).Google Scholar
Shen, S., Jiang, J., Guo, P., Kronawitter, C.X., Mao, S.S., and Guo, L.: Effect of Cr doping on the photoelectrochemical performance of hematite nanorod photoanodes. Nano Energy 1, 732 (2012).Google Scholar
Xi, L., Chi, S., Mak, W.F., Tran, P.D., Barber, J., Loo, S.C.J., and Wong, L.H.: A novel strategy for surface treatment on hematite photoanode for efficient water oxidation. Chem. Sci. 4, 164 (2013).Google Scholar
Cheng, W., He, J., Sun, Z., Peng, Y., Yao, T., Liu, Q., Jiang, Y., Hu, F., Xie, Z., He, B., and Wei, S.: Ni-doped overlayer hematite nanotube: A highly photoactive architecture for utilization of visible light. J. Phys. Chem. C 116, 24060 (2012).Google Scholar
Franking, R., Li, L., Lukowski, M.A., Meng, F., Tan, Y., Hamers, R.J., and Jin, S.: Facile post-growth doping of nanostructured hematite photoanodes for enhanced photoelectrochemical water oxidation. Energy Environ. Sci. 6, 500 (2013).Google Scholar
Mayer, M.T., Lin, Y., Yuan, G., and Wang, D.: Forming heterojunctions at the nanoscale for improved photoelectrochemical water splitting by semiconductor materials: Case studies on hematite. Acc. Chem. Res. 46, 1558 (2013).Google Scholar
Luo, W., Yu, T., Wang, Y., Li, Z., Ye, J., and Zou, Z.: Enhanced photocurrent–voltage characteristics of WO3/Fe2O3 nano-electrodes. J. Phys. D: Appl. Phys. 40, 1091 (2007).Google Scholar
Kronawitter, C.X., Vayssieres, L., Shen, S., Guo, L., Wheeler, D.A., Zhang, J., Antoun, B.R., and Mao, S.S.: A perspective on solar-driven water splitting with all-oxide hetero-nanostructures. Energy Environ. Sci. 4, 3889 (2011).CrossRefGoogle Scholar
Dhanasekaran, P., Salunke, H.G., and Gupta, N.M.: Visible-light-induced photosplitting of water over γ′-Fe4N and γ′-Fe4N/α-Fe2O3 nanocatalysts. J. Phys. Chem. C 116, 12156 (2012).Google Scholar
Miao, C., Ji, S., Xu, G., Liu, G., Zhang, L., and Ye, C.: Micro-nano-structured Fe2O3:Ti/ZnFe2O4 heterojunction films for water oxidation. ACS Appl. Mater. Interfaces 4, 4428 (2012).Google Scholar
Hou, Y., Zuo, F., Dagg, A., and Feng, P.: A three-dimensional branched cobalt-doped α-Fe2O3 nanorod/MgFe2O4 heterojunction array as a flexible photoanode for efficient photoelectrochemical water oxidation. Angew. Chem. Int. Ed. 52, 1248 (2013).Google Scholar
Mayer, M.T., Du, C., and Wang, D.: Hematite/Si nanowire dual-absorber system for photoelectrochemical water splitting at low applied potentials. J. Am. Chem. Soc. 134, 12406 (2012).Google Scholar
Li, J., Meng, F., Suri, S., Ding, W., Huang, F., and Wu, N.: Photoelectrochemical performance enhanced by a nickel oxide–hematite p–n junction photoanode. Chem. Commun. 48, 8213 (2012).Google Scholar
Lin, Y., Xu, Y., Mayer, M.T., Simpson, Z.I., McMahon, G., Zhou, S., and Wang, D.: Growth of p-type hematite by atomic layer deposition and its utilization for improved solar water splitting. J. Am. Chem. Soc. 134, 5508 (2012).Google Scholar
Lin, Y., Zhou, S., Sheehan, S.W., and Wang, D.: Nanonet-based hematite heteronanostructures for efficient solar water splitting. J. Am. Chem. Soc. 133, 2398 (2011).Google Scholar
Yu, B. and Kwak, S.Y.: Carbon quantum dots embedded with mesoporous hematite nanospheres as efficient visible light-active photocatalysts. J. Mater. Chem. 22, 8345 (2012).Google Scholar
Liu, Y., Wang, D., Yu, Y., and Zhang, W.: Preparation and photoelectrochemical properties of functional carbon nanotubes and Ti co-doped Fe2O3 thin films. Int. J. Hydrogen Energy 37, 9566 (2012).Google Scholar
He, L., Jing, L., Li, Z., Sun, W., and Liu, C.: Enhanced visible photocatalytic activity of nanocrystalline α-Fe2O3 by coupling phosphate-functionalized graphene. RSC Adv. 3, 7438 (2013).Google Scholar
Kim, J.Y., Jang, J.W., Youn, D.H., Kim, J.Y., Kim, E.S., and Lee, J.S.: Graphene–carbon nanotube composite as an effective conducting scaffold to enhance the photoelectrochemical water oxidation activity of a hematite film. RSC Adv. 2, 9415 (2012).Google Scholar
Hou, Y., Zuo, F., Dagg, A., and Feng, P.: Visible light-driven α-Fe2O3 nanorod/graphene/BiV1−xMoxO4 core/shell heterojunction array for efficient photoelectrochemical water splitting. Nano Lett. 12, 6464 (2012).Google Scholar
Pendlebury, S.R., Barroso, M., Cowan, A.J., Sivula, K., Tang, J., Grätzel, M., Kluga, D., and Durrant, J.R.: Dynamics of photogenerated holes in nanocrystalline α-Fe2O3 electrodes for water oxidation probed by transient absorption spectroscopy. Chem. Commun. 47, 716 (2011).Google Scholar
Yang, J., Wang, D., Han, H., and Li, C.: Roles of cocatalysts in photocatalysis and photoelectrocatalysis. Acc. Chem. Res. 46, 1990 (2013).Google Scholar
Yokoyama, D., Hashiguchi, D., Maeda, K., Minegishi, T., Takata, T., Abe, R., Kubota, J., and Domen, K.: Ta3N5 photoanodes for water splitting prepared by sputtering. Thin Solid Films. 519(7), 2087 (2011).Google Scholar
Maeda, K., Higashi, M., Siritanaratkul, B., Abe, R., and Domen, K.: SrNbO2N as a water-splitting photoanode with a wide visible light absorption band. J. Am. Chem. Soc. 133, 12334 (2011).Google Scholar
Le Paven-Thivet, C., Ishikawa, A., Ziani, A., Le Gendre, L., Yoshida, M., Kubota, J., Tessier, F., and Domen, K.: Photoelectrochemical properties of crystalline perovskite lanthanum titanium oxynitride films under visible light. J. Phys. Chem. C 113, 6156 (2009).Google Scholar
Tilley, S.D., Cornuz, M., Sivula, K., and Grätzel, M.: Light-induced water splitting with hematite: Improved nanostructure and iridium oxide catalysis. Angew. Chem. Int. Ed. 49, 6405 (2010).Google Scholar
Badia-Bou, L., Mas-Marza, E., Rodenas, P., Barea, E.M., Fabregat-Santiago, F., Gimenez, S., Peris, E., and Bisquert, J.: Water oxidation at hematite photoelectrodes with an iridium-based catalyst. J. Phys. Chem. C 117, 3826 (2013).Google Scholar
Sun, K., Park, N., Sun, Z., Zhou, J., Wang, J., Pang, X., Shen, S., Noh, S., Jing, Y., Jin, S., Yu, P.K.L., and Wang, D.: Nickel oxide functionalized silicon for efficient photo-oxidation of water. Energy Environ. Sci. 5, 7872 (2012).Google Scholar
Sun, K., Pang, X., Shen, S., Qian, X., Cheung, J.S., and Wang, D.: Metal oxide composite enabled nanotextured Si photoanode for efficient solar driven water oxidation. Nano Lett. 13, 2064 (2013).Google Scholar
Wang, G., Ling, Y., Lu, X., Zhai, T., Qian, F., Tong, Y., and Li, Y.: A mechanistic study into the catalytic effect of Ni(OH)2 on hematite for photoelectrochemical water oxidation. Nanoscale 5, 4129 (2013).Google Scholar
Alan, K.S., Hu, Y., Stucky, G.D., and McFarland, E.W.: NiFe-oxide electrocatalysts for the oxygen evolution reaction on Ti doped hematite photoelectrodes. Electrochem. Commun. 11, 1150 (2009).Google Scholar
Elizarova, G.L., Zhidomirov, G.M., and Parmon, V.N.: Hydroxides of transition metals as artificial catalysts for oxidation of water to dioxygen. Catal. Today 58, 71 (2000).Google Scholar
Artero, V., Chavarot-Kerlidou, M., and Fontecave, M.: Splitting water with cobalt. Angew. Chem. Int. Ed. 50, 7238 (2011).Google Scholar
Majumder, S.A. and Khan, S.U.M.: Photoelectrolysis of water at bare and electrocatalyst covered thin film iron oxide electrode. Int. J. Hydrogen Energy 19, 881 (1994).Google Scholar
Jiao, F. and Frei, H.: Nanostructured cobalt oxide clusters in mesoporous silica as efficient oxygen-evolving catalysts. Angew. Chem. Int. Ed. 48, 1841 (2009).Google Scholar
Jiao, F. and Frei, H.: Nanostructured manganese oxide clusters supported on mesoporous silica as efficient oxygen-evolving catalysts. Chem. Commun. 46, 2920 (2010).Google Scholar
Xi, L., Tran, P.D., Chiam, S.Y., Bassi, P.S., Mak, W.F., Mulmudi, H.K., Batabyal, S.K., Barber, J., Loo, J.S.C., and Wong, L.H.: Co3O4-decorated hematite nanorods as an effective photoanode for solar water oxidation. J. Phys. Chem. C 116, 13884 (2012).Google Scholar
Riha, S.C., Klahr, B.M., Tyo, E.C., Seifert, S., Vajda, S., Pellin, M.J., Hamann, T.W., and Martinson, A.B.F.: Atomic layer deposition of a sub-monolayer catalyst for the enhanced photoelectrochemical performance of water oxidation with hematite. ACS Nano 7, 2396 (2013).Google Scholar
Kanan, M.W. and Nocera, D.G.: In situ formation of an oxygen-evolving catalyst in neutral water containing phosphate and Co2+ . Science 321, 1072 (2008).Google Scholar
Zhong, D.K., Sun, J., Inumaru, H., and Gamelin, D.R.: Solar water oxidation by composite catalyst/α-Fe2O3 photoanodes. J. Am. Chem. Soc. 131, 6086 (2009).Google Scholar
Zhong, D.K. and Gamelin, D.R.: Photoelectrochemical water oxidation by cobalt catalyst (“Co-Pi”)/α-Fe2O3 composite photoanodes: Oxygen evolution and resolution of a kinetic bottleneck. J. Am. Chem. Soc. 132, 4202 (2010).Google Scholar
Zhong, D.K., Cornuz, M., Sivula, K., Grätzel, M., and Gamelin, D.R.: Photo-assisted electrodeposition of cobalt–phosphate (Co–Pi) catalyst on hematite photoanodes for solar water oxidation. Energy Environ. Sci. 4, 1759 (2011).Google Scholar
Klahr, B., Gimenez, S., Santiago, F.F., Bisquert, J., and Hamann, T.W.: Photoelectrochemical and impedance spectroscopic investigation of water oxidation with “Co–Pi”-coated hematite electrodes. J. Am. Chem. Soc. 134, 16693 (2012).Google Scholar
Barroso, M., Cowan, A.J., Pendlebury, S.R., Grätzel, M., Klug, D.R., and Durrant, J.R.: The role of cobalt phosphate in enhancing the photocatalytic activity of α-Fe2O3 toward water oxidation. J. Am. Chem. Soc. 133, 14868 (2011).Google Scholar
Hong, Y., Liu, Z., Al-Bukhari, S.F.B.S.A., Lee, C.J.J., Yung, D.L., Chi, D., and Hor, T.S.A.: Effect of oxygen evolution catalysts on hematite nanorods for solar water oxidation. Chem. Commun. 47, 10653 (2011).Google Scholar
Chen, X., Ren, X., Liu, Z., Zhuang, L., and Lu, J.: Promoting the photoanode efficiency for water splitting by combining hematite and molecular Ru catalysts. Electrochem. Commun. 27, 148 (2013).Google Scholar
Klahr, B., Gimenez, S., Santiago, F.F., Hamann, T., and Bisquert, J.: Water oxidation at hematite photoelectrodes: The role of surface states. J. Am. Chem. Soc. 134, 4294 (2012).Google Scholar
Le Formal, F., Tétreault, N., Cornuz, M., Moehl, T., Grätzel, M., and Sivula, K.: Passivating surface states on water splitting hematite photoanodes with alumina overlayers. Chem. Sci. 2, 737 (2011).Google Scholar
Hisatomi, T., Le Formal, F., Cornuz, M., Brillet, J., Tétreault, N., Sivula, K., and Grätzel, M.: Cathodic shift in onset potential of solar oxygen evolution on hematite by 13-group oxide overlayers. Energy Environ. Sci. 4, 2512 (2011).Google Scholar
Leroy, C.M., Maegli, A.E., Sivula, K., Hisatomi, T., Xanthopoulos, N., Otal, E.H., Yoon, S., Weidenkaff, A., Sanjines, R., and Grätzel, M.: LaTiO2N/In2O3 photoanodes with improved performance for solar water splitting. Chem. Commun. 48, 820 (2012).Google Scholar
Le Formal, F., Sivula, K., and Grätzel, M.: The transient photocurrent and photovoltage behavior of a hematite photoanode under working conditions and the influence of surface treatments. J. Phys. Chem. C 116, 26707 (2012).CrossRefGoogle Scholar
Barroso, M., Mesa, C.A., Pendlebury, S.R., Cowan, A.J., Hisatomi, T., Sivula, K., Grätzel, M., Klug, D.R., and Durrant, J.R.: Dynamics of photogenerated holes in surface modified α-Fe2O3 photoanodes for solar water splitting. Proc. Natl. Acad. Sci. U.S.A. 109, 15640 (2012).Google Scholar
Xi, L., Bassi, P.S., Chiam, S.Y., Mak, W.F., Tran, P.D., Barber, J., Loo, J.S.C., and Wong, L.H.: Surface treatment of hematite photoanodes with zinc acetate for water oxidation. Nanoscale 4, 4430 (2012).Google Scholar
Zhang, M., Luo, W., Zhang, N., Li, Z., Yu, T., and Zou, Z.: A facile strategy to passivate surface states on the undoped hematite photoanode for water splitting. Electrochem. Commun. 23, 41 (2012).CrossRefGoogle Scholar
Le Formal, F., Grätzel, M., and Sivula, K.: Controlling photoactivity in ultrathin hematite films for solar water-splitting. Adv. Funct. Mater. 20, 1099 (2010).Google Scholar
Hisatomi, T., Brillet, J., Cornuz, M., Le Formal, F., Tétreault, N., Sivula, K., and Grätzel, M.: A Ga2O3 underlayer as an isomorphic template for ultrathin hematite films toward efficient photoelectrochemical water splitting. Faraday Discuss. 155, 223 (2012).Google Scholar
Hisatomi, T., Dotan, H., Stefik, M., Sivula, K., Rothschild, A., Grätzel, M., and Mathews, N.: Enhancement in the performance of ultrathin hematite photoanode for water splitting by an oxide underlayer. Adv. Mater. 24, 2699 (2012).Google Scholar
Dotan, H., Kfir, O., Sharlin, E., Blank, O., Gross, M., Dumchin, I., Ankonina, G., and Rothschild, A.: Resonant light trapping in ultrathin films for water splitting. Nat. Mater. 12, 158 (2013).Google Scholar
Liao, P., Keith, J.A., and Carter, E.A.: Water oxidation on pure and doped hematite (0001) surfaces: Prediction of Co and Ni as effective dopants for electrocatalysis. J. Am. Chem. Soc. 134, 13296 (2012).Google Scholar
Liao, P. and Carter, E.A.: Hole transport in pure and doped hematite. J. Appl. Phys. 112, 013701 (2012).Google Scholar
Huang, Z., Lin, Y., Xiang, X., Córdoba, W.R., McDonald, K.J., Hagen, K.S., Choi, K.S., Brunschwig, B.S., Musaev, D.G., Hill, C.L., Wang, D., and Lian, T.: In situ probe of photocarrier dynamics in water-splitting hematite (α-Fe2O3) electrodes. Energy Environ. Sci. 5, 8923 (2012).Google Scholar
Kronawitter, C.X., Zegkinoglou, I., Rogero, C., Guo, J.H., Mao, S.S., Himpsel, F.J., and Vayssieres, L.: On the interfacial electronic structure origin of efficiency enhancement in hematite photoanodes. J. Phys. Chem. C 116, 22780 (2012).Google Scholar
Kronawitter, C.X., Bakke, J.R., Wheeler, D.A., Wang, W., Chang, C., Antoun, B.R., Zhang, J., Guo, J., Bent, S.F., Mao, S.S., and Vayssieres, L.: Electron enrichment in 3d transition metal oxide hetero-nanostructures. Nano Lett. 11, 3855 (2011).Google Scholar
Peter, L.M.: Energetics and kinetics of light-driven oxygen evolution at semiconductor electrodes: The example of hematite. J. Solid State Electrochem. 17, 315 (2013).Google Scholar
Cummings, Y., Marken, F., Peter, L.M., Tahir, A.A., and Wijayantha, G.U.: Kinetics and mechanism of light-driven oxygen evolution at thin film α-Fe2O3 electrodes. Chem. Commun. 48, 2027 (2012).Google Scholar
Klahr, B., Gimenez, S., Santiago, F.F., Bisquert, J., and Hamann, T.W.: Electrochemical and photoelectrochemical investigation of water oxidation with hematite electrodes. Energy Environ. Sci. 5, 7626 (2012).CrossRefGoogle Scholar
Cummings, C.Y., Marken, F., Peter, L.M., Wijayantha, K.G.U., and Tahir, A.A.: New insights into water splitting at mesoporous α-Fe2O3 films: A study by modulated transmittance and impedance spectroscopies. J. Am. Chem. Soc. 134, 1228 (2012).Google Scholar