Exploring the interplay of Ti-Sn co-doping in photoelectrochemical water splitting of hematite nanowires

Abstract

Photoelectrochemical water splitting is a promising alternative for sustainable energy production, addressing the growing need for clean energy sources. Hematite is a potential semiconductor for this process due to its abundance, low cost, non-toxicity, and stability. However, bare-hematite-based photoelectrochemical cells face challenges such as low photocurrent density, requiring innovative strategies to improve efficiency. This study explores the combined effects of three key approaches: enhancing crystallinity through high-temperature annealing, increasing specific surface area via nanostructuring, and improving photoanode conductivity through heteroatom doping. Hematite nanowires were synthesized using a hydrothermal method, with Ti-doping introduced during hydrothermal synthesis and subsequent Sn co-doping during an 800 °C annealing process, which also improved crystallinity. The introduction of Ti dopant significantly increased the photocurrent density under simulated solar illumination from 0.03 mA·cm^-2 to 0.63 mA·cm^-2. Co-doping with Ti and Sn further enhanced performance to 1.27 mA·cm^-2. The research explores how heteroatom doping influences the properties of hematite and examines its interaction with high-temperature annealing. These findings are significant for advancing the design of efficient nanostructures for energy conversion applications.

Keywords

Hematite / hydrogen production / heteroatom doping / nanostructuring / photoelectrochemistry / photoanodes

References

[1] Jackson RB,Bousquet P.Increasing anthropogenic methane emissions arise equally from agricultural and fossil fuel sources.Environ Res Lett2020;15:071002

[2] Sudhaik A,Raizada P.Strategies based review on near-infrared light-driven bismuth nanocomposites for environmental pollutants degradation.Chemosphere2022;291:132781

[3] Ullah S,Majeed MT.The asymmetric effects of oil price changes on environmental pollution: evidence from the top ten carbon emitters.Environ Sci Pollut Res2020;27:29623-35

[4] Grätzel M.Photoelectrochemical cells.Nature2001;414:338-44

[5] Dias P,Lopes T,Mendes A.Extremely stable bare hematite photoanode for solar water splitting.Nano Energy2016;23:70-9

[6] Sivula K,Grätzel M.Solar water splitting: progress using hematite (α-Fe₂O₃) photoelectrodes.ChemSusChem2011;4:432-49

[7] Murphy A,Randeniya L.Efficiency of solar water splitting using semiconductor electrodes.Int J Hydrogen Energy2006;31:1999-2017

[8] Tamirat AG,Dubale AA,Hwang BJ.Using hematite for photoelectrochemical water splitting: a review of current progress and challenges.Nanoscale Horiz2016;1:243-67

[9] Dias P,Mendes A.Hematite-based photoelectrode for solar water splitting with very high photovoltage.Nano Energy2017;38:218-31

[10] Formal F, Tétreault N, Cornuz M, Moehl T, Grätzel M, Sivula K. Passivating surface states on water splitting hematite photoanodes with alumina overlayers.Chem Sci2011;2:737-43

[11] Ling Y,Wheeler DA,Li Y.Sn-doped hematite nanostructures for photoelectrochemical water splitting.Nano Lett2011;11:2119-25

[12] Quitério P,Navas D.Photoelectrochemical water splitting: thermal annealing challenges on hematite nanowires.J Phys Chem C2020;124:12897-911

[13] Zandi O.Enhanced water splitting efficiency through selective surface state removal.J Phys Chem Lett2014;5:1522-6

[14] Bassi PS,Boix PP,Barber J.Crystalline Fe₂O₃/Fe₂TiO₅ heterojunction nanorods with efficient charge separation and hole injection as photoanode for solar water oxidation.Nano Energy2016;22:310-8

[15] Zhou D.Recent strategies to enhance the efficiency of hematite photoanodes in photoelectrochemical water splitting.Chin J Catal2021;42:904-19

[16] Ni S,Guo F.Efficiency improvement of TiO₂ nanowire arrays based dye-sensitized solar cells through further enhancing the specific surface area.J Cryst Growth2019;505:62-8

[17] Dhara A,Baral A.Core-shell CuO-ZnO p-n heterojunction with high specific surface area for enhanced photoelectrochemical (PEC) energy conversion.Solar Energy2016;136:327-32

[18] Haider Z,Lee HW.Surface and bulk modification for advanced electrode design in photoelectrochemical water splitting.Int J Hydrogen Energy2020;45:5793-815

[19] Park J,Chaule S.Recent progress and perspectives on heteroatom doping of hematite photoanodes for photoelectrochemical water splitting.J Mater Chem A2023;11:24551-65

[20] Dias P,Andrade L.Temperature effect on water splitting using a Si-doped hematite photoanode.J Power Sources2014;272:567-80

[21] Niu S,Wei Z.Se-doping activates FeOOH for cost-effective and efficient electrochemical water oxidation.J Am Chem Soc2019;141:7005-13

[22] Wang J,Zhang W.Integrating Cr doped FeOOH into FeSe₂ nanoparticles for efficient water oxidation at large current densities.Fuel2023;351:128827

[23] Lin J,Zhou L,Qin G.Pt-doped α-Fe₂O₃ photoanodes prepared by a magnetron sputtering method for photoelectrochemical water splitting.Mater Res Bull2017;91:214-9

[24] Gurudayal ,Kumar MH.Improving the efficiency of hematite nanorods for photoelectrochemical water splitting by doping with manganese.ACS Appl Mater Interfaces2014;6:5852-9

[25] Shen S,Guo P,Mao SS.Effect of Cr doping on the photoelectrochemical performance of hematite nanorod photoanodes.Nano Energy2012;1:732-41

[26] Liu J,Tian Z.Highly oriented Ge-doped hematite nanosheet arrays for photoelectrochemical water oxidation.Nano Energy2014;9:282-90

[27] Shen S,Jiang J,Guo L.Surface tuning for promoted charge transfer in hematite nanorod arrays as water-splitting photoanodes.Nano Res2012;5:327-36

[28] Zhang M,Li Z,Zou Z.Surface modification of hematite photoanode films with rhodium.Rare Met2011;30:38-41

[29] Sivula K,Le Formal F.Photoelectrochemical water splitting with mesoporous hematite prepared by a solution-based colloidal approach.J Am Chem Soc2010;132:7436-44

[30] Cesar I,Kay A,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 C2009;113:772-82

[31] Malviya KD,Shlenkevich D,Mor H.Systematic comparison of different dopants in thin film hematite (α-Fe₂O₃) photoanodes for solar water splitting.J Mater Chem A2016;4:3091-9

[32] Zhang Y,Ma W,Song W.Doping-promoted solar water oxidation on hematite photoanodes.Molecules2016;21:868 PMCID:PMC6274439

[33] Quang ND,Le DD.Fluorine-surface-modified tin-doped hematite nanorod array photoelectrodes with enhanced water oxidation activity.Appl Surf Sci2021;558:149898

[34] Quang N, Cao Van P, Majumder S, Jeong JR, Kim D, Kim C. Rational construction of S-doped FeOOH onto Fe₂O₃ nanorods for enhanced water oxidation.J Colloid Interface Sci2022;616:749-58

[35] Barroso M,Pendlebury SR.Dynamics of photogenerated holes in surface modified α-Fe₂O₃ photoanodes for solar water splitting.Proc Natl Acad Sci U S A2012;109:15640-5

[36] Kim JH,Pan Z.Revealing the roles of surface treatments on hematite (α-Fe₂O₃) photoanode in the shift of the onset potential.J Photochem Photobiol A Chem2023;445:115037

[37] Franking R,Lukowski MA.Facile post-growth doping of nanostructured hematite photoanodes for enhanced photoelectrochemical water oxidation.Energy Environ Sci2013;6:500-12

[38] Pu A,Li M.Coupling Ti-doping and oxygen vacancies in hematite nanostructures for solar water oxidation with high efficiency.J Mater Chem A2014;2:2491

[39] Su J,Zong S,Liu C.The effect of thermal annealing on the interfacial properties and photoelectrochemical performance of Ti doped Fe₂O₃ nanowire arrays.RSC Adv2016;6:99851-8

[40] Peng Y,Lam CH.Plasma-implanted Ti-doped hematite photoanodes with enhanced photoelectrochemical water oxidation performance.J Alloys Compd2021;870:159376

[41] Shen S,Wheeler DA.Physical and photoelectrochemical characterization of Ti-doped hematite photoanodes prepared by solution growth.J Mater Chem A2013;1:14498

[42] Zhang P,Hu Y.Oriented Ti doped hematite thin film as active photoanodes synthesized by facile APCVD.Energy Environ Sci2011;4:1020

[43] Ling Y.Review of Sn-doped hematite nanostructures for photoelectrochemical water splitting.Part Part Syst Charact2014;31:1113-21

[44] Vayssieres L,Lindquist S.Controlled aqueous chemical growth of oriented three-dimensional crystalline nanorod arrays:  application to iron(III) oxides.Chem Mater2001;13:233-5

[45] Francisco F,Ivanou D,Azevedo J.Synthesis of Host-guest hematite photoelectrodes for solar water splitting.ChemNanoMat2019;5:911-20

[46] Yang T,Jin K.An iron oxide photoanode with hierarchical nanostructure for efficient water oxidation.J Mater Chem A2014;2:2297-305

[47] Schneider CA,Eliceiri KW.NIH image to imageJ: 25 years of image analysis.Nat Methods2012;9:671-5 PMCID:PMC5554542

[48] Seah MP.Quantitative electron spectroscopy of surfaces: a standard data base for electron inelastic mean free paths in solids.Surf Interface Anal1979;1:2-11

[49] Redondo-cubero A,Gordillo N.Current status and future developments of the ion beam facility at the centre of micro-analysis of materials in Madrid.Eur Phys J Plus2021;136:1085

[50] Mayer M. SIMNRA, a simulation program for the analysis of NRA, RBS and ERDA. In: The fifteenth international conference on the application of accelerators in research and industry; Denton, Texas (USA): AIP; 1999. pp. 541-4. Available from: https://pubs.aip.org/aip/acp/article/475/1/541-544/953322. [Last accessed on 21 Mar 2025]

[51] Lopes T,Le Formal F,Sivula K.Hematite photoelectrodes for water splitting: evaluation of the role of film thickness by impedance spectroscopy.Phys Chem Chem Phys2014;16:16515-23

[52] Dare-edwards MP,Hamnett A.Electrochemistry and photoelectrochemistry of iron(III) oxide.J Chem Soc, Faraday Trans 11983;79:2027

[53] Ahn H,Lee J,Jang J.Nanoporous hematite structures to overcome short diffusion lengths in water splitting.J Mater Chem A2014;2:19999-20003

[54] Dotan H,Hisatomi T,Rothschild A.On the solar to hydrogen conversion efficiency of photoelectrodes for water splitting.J Phys Chem Lett2014;5:3330-4

[55] Dotan H,Grätzel M,Warren SC.Probing the photoelectrochemical properties of hematite (α-Fe₂O₃ ) electrodes using hydrogen peroxide as a hole scavenger.Energy Environ Sci2011;4:958-64

[56] Morrish R,MacElroy JM.Activation of hematite nanorod arrays for photoelectrochemical water splitting.ChemSusChem2011;4:474-9

[57] Zhao X,Wang N.The Influence of Ti doping on morphology and photoelectrochemical properties of hematite grown from aqueous solution for water splitting.Energy Tech2018;6:2188-99

[58] Mazzaro R,Natali M.Hematite nanostructures: an old material for a new story. Simultaneous photoelectrochemical oxidation of benzylamine and hydrogen production through Ti doping.Nano Energy2019;61:36-46

[59] Deng J,Pu A.Ti-doped hematite nanostructures for solar water splitting with high efficiency.J Appl Phys2012;112:084312

[60] Li L,Liu C,Mitsuzaki N.The effect of annealing regime and electrodeposition time on morphology and photoelecrochemical performance of hematite converted from nanosheet γ-FeOOH.J Photochem Photobiol A Chem2019;369:8-15

[61] Kay A,Grätzel M.New benchmark for water photooxidation by nanostructured alpha-Fe₂O₃ films.J Am Chem Soc2006;128:15714-21

[62] Iordanova N,Rosso KM.Charge transport in metal oxides: a theoretical study of hematite alpha-Fe₂O₃.J Chem Phys2005;122:144305

[63] Zhang H,Bao X.Fabrication of hematite photoanode consisting of (110)-oriented single crystals.ChemSusChem2023;16:e202300666

[64] Suryanarayana C. X-ray diffraction. 1th ed. Boston, MA: Springer US; 1998. Available from: http://link.springer.com/10.1007/978-1-4899-0148-4. [Last accessed on 21 Mar 2025]

[65] Williamson G.X-ray line broadening from filed aluminium and wolfram.Acta Metall1953;1:22-31

[66] Maabong K,Mwankemwa BS.Nanostructured hematite thin films for photoelectrochemical water splitting.Physica B2018;535:67-71

[67] Apolinário A,Costa C,Mendes AM.Multilayered WO₃ nanoplatelets for efficient photoelectrochemical water splitting: the role of the annealing ramp.ACS Appl Energy Mater2019;2:1040-50

[68] Oliveira G,Pires A,Araújo J.Magnetocaloric effect and refrigerant capacity in polycrystalline YCrO₃.J Phys Chem Solids2016;91:182-8

[69] Proenca MP,Pereira AM.Size and surface effects on the magnetic properties of NiO nanoparticles.Phys Chem Chem Phys2011;13:9561-7

[70] Shannon RD.Revised effective ionic radii and systematic studies of interatomic distances in halides and chalcogenides.Acta Cryst A1976;32:751-67

[71] Bhandary N,Ingole PP.Enhanced photoelectrochemical performance of electrodeposited hematite films decorated with nanostructured NiMnO_x.RSC Adv2016;6:35239-47

[72] Zhang X,Meng X,Zhao J.Structural evolution and characteristics of the phase transformations between α-Fe₂O₃, Fe₃O₄ and γ-Fe₂O₃ nanoparticles under reducing and oxidizing atmospheres.CrystEngComm2013;15:8166

[73] Sarma SK,Shukla A.Structural, opto-electronic and photoelectrochemical properties of tin doped hematite nanoparticles for water splitting.Mater Sci Semicond Process2020;108:104873

[74] Shirley DA.High-resolution X-ray photoemission spectrum of the valence bands of gold.Phys Rev B1972;5:4709-14

[75] Zhang J,Wang L.Synthesis and gas sensing properties of α-Fe₂O₃@ZnO core-shell nanospindles.Nanotechnology2011;22:185501

[76] Fu Y,Xu J.Synthesis of large arrays of aligned α-Fe₂O₃ nanowires.Chem Phys Lett2003;379:373-9

[77] Kang MJ,Lee W.Efficient Fe₂O₃/C-g-C₃N₄ Z-scheme heterojunction photocatalyst prepared by facile one-step carbonizing process.J Phys Chem Solids2019;130:93-9

[78] Biesinger MC.Accessing the robustness of adventitious carbon for charge referencing (correction) purposes in XPS analysis: Insights from a multi-user facility data review.Appl Surf Sci2022;597:153681

[79] Grosvenor AP,Biesinger MC.Investigation of multiplet splitting of Fe 2p XPS spectra and bonding in iron compounds.Surf Interface Anal2004;36:1564-74

[80] Hao S,Yang R.Corn-like mesoporous SnO₂/α-Fe₂O₃ heterostructure for superior TEA sensing performance.Appl Phys A2021;127:4350

[81] Sun L,Yang S.Template and silica interlayer tailorable synthesis of spindle-like multilayer α-Fe₂O₃/Ag/SnO₂ ternary hybrid architectures and their enhanced photocatalytic activity.ACS Appl Mater Interfaces2014;6:1113-24

[82] Biesinger MC,Grosvenor AP,Gerson AR.Resolving surface chemical states in XPS analysis of first row transition metals, oxides and hydroxides: Cr, Mn, Fe, Co and Ni.Appl Surf Sci2011;257:2717-30

[83] Payne B,Mcintyre N.X-ray photoelectron spectroscopy studies of reactions on chromium metal and chromium oxide surfaces.J Electron Spectrosc Relat Phenom2011;184:29-37

[84] Wang L,Zhang Y,Schmuki P.Enhanced solar water splitting by swift charge separation in Au/FeOOH sandwiched single-crystalline Fe₂O₃ nanoflake photoelectrodes.ChemSusChem2017;10:2720-7

[85] Tian CM,Lin YM.Electronic structure, optical properties, and photoelectrochemical activity of Sn-doped Fe₂O₃ thin films.J Phys Chem C2020;124:12548-58

[86] Wang J,Guo L,Tuller HL.On the theoretical and experimental control of defect chemistry and electrical and photoelectrochemical properties of hematite nanostructures.ACS Appl Mater Interfaces2019;11:2031-41

[87] Ye F,Ran R.Facile mechanochemical synthesis of nano SnO₂/graphene composite from coarse metallic Sn and graphite oxide: an outstanding anode material for lithium-ion batteries.Chem Eur J2014;20:4055-63

[88] Mancipe S,Pinzón C,Solis D.Effective photocatalytic degradation of Rhodamine B using tin semiconductors over hydrotalcite-type materials under sunlight driven.Catal Today2021;372:191-7

[89] Baggetto L,Meisner RP.Characterization of sodium ion electrochemical reaction with tin anodes: experiment and theory.J Power Sources2013;234:48-59

[90] Lee MH,Han HS.Nanostructured Ti-doped hematite (α-Fe₂O₃) photoanodes for efficient photoelectrochemical water oxidation.Int J Hydrogen Energy2014;39:17501-7

[91] Chae SY,Joo O.Elucidation of the structural and charge separation properties of titanium-doped hematite films deposited by electrospray method for photoelectrochemical water oxidation.Electrochim Acta2019;297:784-93

[92] Lian X,Liu S.Enhanced photoelectrochemical performance of Ti-doped hematite thin films prepared by the sol-gel method.App Surf Sci2012;258:2307-11

[93] Niu Y,Niu P,Ma Y.Effects of Ti doping on hematite photoanodes: more surface states.J Nanosci Nanotechnol2019;19:3437-46

[94] Barradas NP.Rutherford backscattering analysis of thin films and superlattices with roughness.J Phys D Appl Phys2001;34:2109-16

[95] Barradas NP,Redondo-cubero A,Kung P.Analytical simulation of RBS spectra of nanowire samples.Nucl Instrum Methods Phys Res B2016;371:116-20

[96] Klahr B,Fabregat-Santiago F,Bisquert J.Water oxidation at hematite photoelectrodes: the role of surface states.J Am Chem Soc2012;134:4294-302

[97] Jrad F,Ouertani R.Photo-electrochemical impedance spectroscopy analysis of hydrothermally synthesized β-In₂S₃ thin film photo-anodes.Physica E2019;114:113585

[98] Katsuki T,Tanaka K.Facile fabrication of a highly crystalline and well-interconnected hematite nanoparticle photoanode for efficient visible-light-driven water oxidation.ACS Appl Mater Interfaces2021;13:39282-90

[99] Peerakiatkhajohn P,Chen H,Butburee T.Stable hematite nanosheet photoanodes for enhanced photoelectrochemical water splitting.Adv Mater2016;28:6405-10

[100] Liu G,Chen H.Tuning the morphology and structure of disordered hematite photoanodes for improved water oxidation: a physical and chemical synergistic approach.Nano Energy2018;53:745-52

[101] Qin D,Wang T.Sn-doped hematite films as photoanodes for efficient photoelectrochemical water oxidation.J Mater Chem A2015;3:6751-5

[102] Bak A,Park H.Enhancing the photoelectrochemical performance of hematite (α-Fe₂O₃) electrodes by cadmium incorporation.Appl Catal B Environ2011;110:207-15

[103] Jha BK,Jang J.Enhancing photocatalytic efficiency with hematite photoanodes: principles, properties, and strategies for surface, bulk, and interface charge transfer improvement.Mater Chem Front2024;8:2197-226

[104] Yoon K,Lee H.Unveiling the role of the ti dopant and viable Si doping of hematite for practically efficient solar water splitting.ACS Catal2022;12:5112-22

[105] Liu H,Li Y,Jiang W.Hematite-based photoanodes for photoelectrochemical water splitting: performance, understanding, and possibilities.J Environ Chem Eng2023;11:109224

[106] Jeon TH,Park H.Ultra-efficient and durable photoelectrochemical water oxidation using elaborately designed hematite nanorod arrays.Nano Energy2017;39:211-8

[107] Iandolo B,Wickman B,Conibeer G.Correlating flat band and onset potentials for solar water splitting on model hematite photoanodes.RSC Adv2015;5:61021-30

[108] Toroker MC.Theoretical insights into the mechanism of water oxidation on nonstoichiometric and titanium-doped Fe₂O₃(0001).J Phys Chem C2014;118:23162-7

[109] Kamimura J,Abdi FF.Photoelectrochemical properties of GaN photoanodes with cobalt phosphate catalyst for solar water splitting in neutral electrolyte.J Phys Chem C2017;121:12540-5

[110] Bartesaghi D,Kniepert J.Competition between recombination and extraction of free charges determines the fill factor of organic solar cells.Nat Commun2015;6:7083 PMCID:PMC4432638

[111] Dias P,Meda L,Mendes A.Photoelectrochemical water splitting using WO₃ photoanodes: the substrate and temperature roles.Phys Chem Chem Phys2016;18:5232-43

[112] Krol R van de. Photoelectrochemical hydrogen production. 1th ed. New York: Springer; 2012. Available from: https://link.springer.com/book/10.1007/978-1-4614-1380-6. [Last accessed on 21 Mar 2025]

[113] Yu Q,Wang T,Ye J.Hematite films decorated with nanostructured ferric oxyhydroxide as photoanodes for efficient and stable photoelectrochemical water splitting.Adv Funct Materials2015;25:2686-92

[114] Li C,Luo Z.Surviving high-temperature calcination: ZrO₂-induced hematite nanotubes for photoelectrochemical water oxidation.Angew Chem Int Ed2017;56:4150-5

[115] Zhang R,Chen T.Enhanced photoelectrochemical water oxidation performance of Fe₂O₃ nanorods array by S doping.ACS Sustainable Chem Eng2017;5:7502-6