Insights on advanced substrates for controllable fabrication of photoanodes toward efficient and stable photoelectrochemical water splitting

Abstract

Conversion of solar energy into H₂ by photoelectrochemical (PEC) water splitting is recognized as an ideal way to address the growing energy crisis and environmental issues. In a typical PEC cell, the construction of photoanodes is crucial to guarantee the high efficiency and stability of PEC reactions, which fundamentally rely on rationally designed semiconductors (as the active materials) and substrates (as the current collectors). In this review work, we start with a brief introduction of the roles of substrates in the PEC process. Then, we provide a systematic overview of representative strategies for the controlled fabrication of photoanodes on rationally designed substrates, including conductive glass, metal, sapphire, silicon, silicon carbide, and flexible substrates. Finally, some prospects concerning the challenges and research directions in this area are proposed.

Keywords

hydrogen / photoanode / photoelectrochemical / substrates / water splitting

References

[1] Lewis NS, Nocera DG. Powering the planet: chemical challenges in solar energy utilization. Proc Natl Acad Sci USA. 2006; 103 (43): 15729- 15735.

[2] Song W, Li M, Wang C, Lu X. Electronic modulation and interface engineering of electrospun nanomaterials-based electrocatalysts toward water splitting. Carbon Energy. 2021; 3 (1): 101- 128.

[3] Armaroli N, Balzani V. The future of energy supply: challenges and opportunities. Angew Chem Int Ed. 2007; 46 (1-2): 52- 66.

[4] Zhu Z, Guo W, Zhang Y, et al. Research progress on methane conversion coupling photocatalysis and thermocatalysis. Carbon Energy. 2021; 3 (4): 519- 540.

[5] Kim N, Lee J, Gu M, Kim B-S. Modulating charge carriers in carbondots toward efficient solar-to-energy conversion. Carbon Energy. 2021; 3 (590): 614.

[6] Li X, Yu J, Low J, Fang Y, Xiao J, Chen X. Engineering heterogeneous semiconductors for solar water splitting. J Mater Chem A. 2015; 3 (6): 2485- 2534.

[7] Walter MG, Warren EL, McKone JR, et al. Solar water splitting cells. Chem Rev. 2010; 110 (11): 6446- 6473.

[8] Kang D, Kim TW, Kubota SR, Cardiel AC, Cha HG, Choi KS. Electrochemical synthesis of photoelectrodes and catalysts for use in solar water splitting. Chem Rev. 2015; 115 (23): 12839- 12887.

[9] Li J, Yuan H, Zhang W, et al. Advances in Z-scheme semiconductor photocatalysts for the photoelectrochemical applications: a review. Carbon Energy. 2022; 4 (3): 294- 331.

[10] Phuan YW, Ong W-J, Chong MN, Ocon JD. Prospects of electrochemically synthesized hematite photoanodes for photoelectrochemical water splitting: a review. J Photochem Photobiol C. 2017; 33: 54- 82.

[11] Fujishima A, Honda K. Electrochemical photolysis of water at a semiconductor electrode. Nature. 1972; 238 (5358): 37- 38.

[12] Linic S, Christopher P, Ingram DB. Plasmonic-metal nanostructures for efficient conversion of solar to chemical energy. Nat Mater. 2011; 10 (12): 911- 921.

[13] Volokh M, Peng G, Barrio J, Shalom M. Carbon nitride materials for water splitting photoelectrochemical cells. Angew Chem Int Ed. 2019; 58 (19): 6138- 6151.

[14] Samuel E, Joshi B, Kim M-W, Swihart MT, Yoon SS. Morphology engineering of photoelectrodes for efficient photoelectrochemical water splitting. Nano Energy. 2020; 72: 104648.

[15] Yang W, Moon J. Recent advances in earth-abundant photocathodes for photoelectrochemical water splitting. ChemSusChem. 2019; 12 (9): 1889- 1899.

[16] Jang YJ, Lee JS. Photoelectrochemical water splitting with ptype metal oxide semiconductor photocathodes. ChemSusChem. 2019; 12 (9): 1835- 1845.

[17] Chen Q, Fan G, Fu H, Li Z, Zou Z. Tandem photoelectrochemical cells for solar water splitting. Adv Phys X. 2018; 3 (1): 1487267.

[18] Park Y, McDonald KJ, Choi K-S. Progress in bismuth vanadate photoanodes for use in solar water oxidation. Chem Soc Rev. 2013; 42 (6): 2321- 2337.

[19] Zhang P, Zhang J, Gong J. Tantalum-based semiconductors for solar water splitting. Chem Soc Rev. 2014; 43 (13): 4395- 4422.

[20] Li J, Wu N. Semiconductor-based photocatalysts and photoelectrochemical cells for solar fuel generation: a review. Catal Sci Technol. 2015; 5 (3): 1360- 1384.

[21] Zhen C, Chen R, Wang L, Liu G, Cheng H-M. Tantalum (oxy)nitride based photoanodes for solar-driven water oxidation. J Mater Chem A. 2016; 4 (8): 2783- 2800.

[22] Alexander BD, Kulesza PJ, Rutkowska I, Solarska R, Augustynski J. Metal oxide photoanodes for solar hydrogen production. J Mater Chem. 2008; 18 (20): 2298- 2303.

[23] Seo J, Nishiyama H, Yamada T, Domen K. Visible-lightresponsive photoanodes for highly active, stable water oxidation. Angew Chem Int Ed. 2018; 57 (28): 8396- 8415.

[24] Lee DK, Lee D, Lumley MA, Choi K-S. Progress on ternary oxide-based photoanodes for use in photoelectrochemical cells for solar water splitting. Chem Soc Rev. 2019; 48 (7): 2126- 2157.

[25] Cowan AJ, Durrant JR. Long-lived charge separated states in nanostructured semiconductor photoelectrodes for the production of solar fuels. Chem Soc Rev. 2013; 42 (6): 2281- 2293.

[26] Hou T-F, Shanmugasundaram A, Bagal IV, Ryu SW, Lee DW. Flexible, polymer-supported, ZnO nanorod array photoelectrodes for PEC water splitting applications. Mater Sci Semicond Process. 2021; 121: 105445.

[27] Kim TW, Choi K-S. Nanoporous BiVO₄ photoanodes with dual-layer oxygen evolution catalysts for solar water splitting. Science. 2014; 343 (6174): 990- 994.

[28] Ning F, Shao M, Xu S, et al. TiO₂/graphene/NiFe-layered double hydroxide nanorod array photoanodes for efficient photoelectrochemical water splitting. Energy Environ Sci. 2016; 9 (8): 2633- 2643.

[29] Yi S-S, Wulan B-R, Yan J-M, Jiang Q. Highly efficient photoelectrochemical water splitting: surface modification of cobalt-phosphate-loaded Co₃O₄/Fe₂O₃ p-n heterojunction nanorod arrays. Adv Funct Mater. 2019; 29 (11): 1801902.

[30] Li Y, Takata T, Cha D, et al. Vertically aligned Ta₃N₅ nanorod arrays for solar-driven photoelectrochemical water splitting. Adv Mater. 2013; 25 (1): 125- 131.

[31] Peerakiatkhajohn P, Yun JH, Chen H, Lyu M, Butburee T, Wang L. Stable hematite nanosheet photoanodes for enhanced photoelectrochemical water splitting. Adv Mater. 2016; 28 (30): 6405- 6410.

[32] Pihosh Y, Nandal V, Minegishi T, et al. Development of a core-shell heterojunction Ta₃N₅-nanorods/BaTaO₂N photoanode for solar water splitting. ACS Energy Lett. 2020; 5 (8): 2492- 2497.

[33] Zhong M, Ma Y, Oleynikov P, Domen K, Delaunay J-J. A conductive ZnO-ZnGaON nanowire-array-on-a-film photoanode for stable and efficient sunlight water splitting. Energy Environ Sci. 2014; 7 (5): 1693- 1699.

[34] Yang C, Xi X, Yu Z, et al. Light modulation and water splitting enhancement using a composite porous GaN structure. ACS Appl Mater Interfaces. 2018; 10 (6): 5492- 5497.

[35] Patil SS, Johar MA, Hassan MA, Patil DR, Ryu S-W. Anchoring MWCNTs to 3D honeycomb ZnO/GaN heterostructures to enhancing photoelectrochemical water oxidation. Appl Catal B. 2018; 237: 791- 801.

[36] Zhao Y, Westerik P, Santbergen R, Zoethout E, Gardeniers H, Bieberle-Hütter A. From geometry to activity: a quantitative analysis of WO₃/Si micropillar arrays for photoelectrochemical water splitting. Adv Funct Mater. 2020; 30 (13): 1909157.

[37] Noh SY, Sun K, Choi C, et al. Branched TiO₂/Si nanostructures for enhanced photoelectrochemical water splitting. Nano Energy. 2013; 2 (3): 351- 360.

[38] Chen H, Wang P, Ye H, et al. Vertically aligned InGaN nanowire arrays on pyramid textured Si (1 0 0): A 3D arrayed light trapping structure for photoelectrocatalytic water splitting. Chem Eng J. 2021; 406: 126757.

[39] Xu S, Jiang F, Gao F, et al. Single-crystal integrated photoanodes based on 4H-SiC nanohole arrays for boosting photoelectrochemical water splitting activity. ACS Appl Mater Interfaces. 2020; 12 (18): 20469- 20478.

[40] Jian JX, Jokubavicius V, Syväjärvi M, Yakimova R, Sun J. Nanoporous cubic silicon carbide photoanodes for enhanced solar water splitting. ACS Nano. 2021; 15 (3): 5502- 5512.

[41] Hou Y, Zuo F, Dagg A, 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. 2013; 52 (4): 1248- 1252.

[42] Hou Y, Qiu M, Zhang T, et al. Efficient electrochemical and photoelectrochemical water splitting by a 3D nanostructured carbon supported on flexible exfoliated graphene foil. Adv Mater. 2017; 29 (3): 1604480.

[43] Li H, Xiao S, Zhou J, et al. A flexible CdS nanorods-carbon nanotubes/stainless steel mesh photoanode for boosted photoelectrocatalytic hydrogen evolution. Chem Commun. 2019; 55 (19): 2741- 2744.

[44] Hufnagel AG, Peters K, Müller A, Scheu C, Fattakhova-Rohlfing D, Bein T. Zinc ferrite photoanode nanomorphologies with favorable kinetics for water-splitting. Adv Funct Mater. 2016; 26 (25): 4435- 4443.

[45] Kuang Y, Jia Q, Ma G, et al. Ultrastable low-bias water splitting photoanodes via photocorrosion inhibition and in situ catalyst regeneration. Nat Energy. 2017; 2 (1): 16191.

[46] Zhang H, Kim JH, Kim JH, Lee JS. Engineering highly ordered iron titanate nanotube array photoanodes forenhanced solar water splitting activity. Adv Funct Mater. 2017; 27 (35): 1702428.

[47] Bhatt MD, Lee JS. Recent theoretical progress in the development of photoanode materials for solar water splitting photoelectrochemical cells. J Mater Chem A. 2015; 3 (20): 10632- 10659.

[48] Qiu Y, Pan Z, Chen H, et al. Current progress in developing metal oxide nanoarrays-based photoanodes for photoelectrochemical water splitting. Sci Bull. 2019; 64 (18): 1348- 1380.

[49] Wang L, Si W, Tong Y, et al. Graphitic carbon nitride (g-C₃N₄)-based nanosized heteroarrays: promising materials for photoelectrochemical water splitting. Carbon Energy. 2020; 2 (2): 223- 250.

[50] Pan J-B, Shen S, Chen L, Au C-T, Yin S-F. Core-shell photoanodes for photoelectrochemical water oxidation. Adv Funct Mater. 2021; 31 (36): 2104269.

[51] Tang R, Zhou S, Zhang Z, Zheng R, Huang J. Engineering nanostructure-interface of photoanode materials toward photoelectrochemical water oxidation. Adv Mater. 2021; 33 (17): 2005389.

[52] Shen S, Lindley SA, Chen X, Zhang JZ. Hematite heterostructures for photoelectrochemical water splitting: rational materials design and charge carrier dynamics. Energy Environ Sci. 2016; 9 (9): 2744- 2775.

[53] Jiang J, Li Y, Liu J, Huang X. Building one-dimensional oxide nanostructure arrays on conductive metal substrates for lithium-ion battery anodes. Nanoscale. 2011; 3 (1): 45- 58.

[54] Skompska M, Zarębska K. Electrodeposition of ZnO nanorod arrays on transparent conducting substrates-a review. Electrochim Acta. 2014; 127: 467- 488.

[55] Wang Z, Wang L. Progress in designing effective photoelectrodes for solar water splitting. Chin J Catal. 2018; 39 (3): 369- 378.

[56] Xin Y, Li Z, Wu W, Fu B, Zhang Z. Pyrite FeS₂ sensitized TiO₂ nanotube photoanode for boosting near-infrared light photoelectrochemical water splitting. ACS Sustainable Chem Eng. 2016; 4 (12): 6659- 6667.

[57] Li L, Xiao S, Li R, et al. Nanotube array-like WO₃ photoanode with dual-layer oxygen-evolution cocatalysts for photoelectrocatalytic overall water splitti. ACS Appl Energy Mater. 2018; 1 (12): 6871- 6880.

[58] Liu D, Ma J, Long R, Gao C, Xiong Y. Silicon nanostructures for solar-driven catalytic applications. Nano Today. 2017; 17: 96- 116.

[59] Li B, Jian J, Chen J, Yu X, Sun J. Nanoporous 6H-SiC photoanodes with a conformal coating of Ni-FeOOH nanorods for zero-onset-potential water splitting. ACS Appl Mater Interfaces. 2020; 12 (6): 7038- 7046.

[60] Sun Y, Rogers JA. Inorganic semiconductors for flexible electronics. Adv Mater. 2007; 19 (15): 1897- 1916.

[61] Teng L, Ye S, Handschuh-Wang S, Zhou X, Gan T, Zhou X. Liquid metal-based transient circuits for flexible and recyclable electronics. Adv Funct Mater. 2019; 29 (11): 1808739.

[62] Kalanur SS, Hwang YJ, Chae SY, Joo OS. Facile growth of aligned WO₃ nanorods on FTO substrate for enhanced photoanodic water oxidation activity. J Mater Chem A. 2013; 1 (10): 3479- 3488.

[63] Kay A, Grave DA, Ellis DS, Dotan H, Rothschild A. Heterogeneous doping to improve the performance of thin-film hematite photoanodes for solar water splitting. ACS Energy Lett. 2016; 1 (4): 827- 833.

[64] Li JM, Cheng HY, Chiu YH, Hsu YJ. ZnO-Au-SnO₂ Z-scheme photoanodes for remarkable photoelectrochemical water splitting. Nanoscale. 2016; 8 (34): 15720- 15729.

[65] Yan L, Zhao W, Liu Z. 1D ZnO/BiVO₄ heterojunction photoanodes for efficient photoelectrochemical water splitting. Dalton Trans. 2016; 45 (28): 11346- 11352.

[66] Zhong Y, Li Z, Zhao X, et al. Enhanced water-splitting performance of perovskite SrTaO₂N photoanode film through ameliorating interparticle charge transport. Adv Funct Mater. 2016; 26 (39): 7156- 7163.

[67] Hegner FS, Herraiz-Cardona I, Cardenas-Morcoso D, López N, Galán-Mascarós JR, Gimenez S. Cobalt hexacyanoferrate on BiVO₄ photoanodes for robust water splitting. ACS Appl Mater Interfaces. 2017; 9 (43): 37671- 37681.

[68] Hilliard S, Baldinozzi G, Friedrich D, et al. Mesoporous thin film WO₃ photoanode for photoelectrochemical water splitting: a sol-gel dip coating approach. Sustainable Energy Fuels. 2017; 1 (1): 145- 153.

[69] Kalanur SS, Yoo I-H, Seo H. Fundamental investigation of Ti doped WO₃ photoanode and their influence on photoelectrochemical water splitting activity. Electrochim Acta. 2017; 254: 348- 357.

[70] Liu Z, Wang X, Cai Q, Ma C, Tong Z. CaBi₆O₁₀: a novel promising photoanode for photoelectrochemical water oxidation. J Mater Chem A. 2017; 5 (18): 8545- 8554.

[71] Tang P, Xie H, Ros C, et al. Enhanced photoelectrochemical water splitting of hematite multilayer nanowire photoanodes by tuning the surface state via bottom-up interfacial engineering. Energy Environ Sci. 2017; 10 (10): 2124- 2136.

[72] Tang R, Zhou S, Yuan Z, Yin L. Metal-organic framework derived Co₃O₄/TiO₂/Si heterostructured nanorod array photoanodes for efficient photoelectrochemical water oxidation. Adv Funct Mater. 2017; 27 (37): 1701102.

[73] Wang S, Chen P, Yun JH, Hu Y, Wang L. An electrochemically treated BiVO₄ photoanode for efficient photoelectrochemical water splitting. Angew Chem Int Ed. 2017; 129 (29): 8620- 8624.

[74] Wang Y, Tian W, Chen L, Cao F, Guo J, Li L. Threedimensional WO₃ Nanoplate/Bi₂S₃ nanorod heterojunction as a highly efficient photoanode for improved photoelectrochemical water splitting. ACS Appl Mater Interfaces. 2017; 9 (46): 40235- 40243.

[75] Yang J-S, Wu J-J. Low-potential driven fully-depleted BiVO₄/ZnO heterojunction nanodendrite array photoanodes for photoelectrochemical water splitting. Nano Energy. 2017; 32: 232- 240.

[76] Zeng Q, Li J, Li L, Bai J, Xia L, Zhou B. Synthesis of WO₃/BiVO₄ photoanode using a reaction of bismuth nitrate with peroxovanadate on WO₃ film for efficient photoelectrocatalytic water splitting and organic pollutant degradation. Appl Catal B. 2017; 217: 21- 29.

[77] Liu L, Hou H, Wang L, et al. A transparent CdS@TiO₂ nanotextile photoanode with boosted photoelectrocatalytic efficiency and stability. Nanoscale. 2017; 9 (40): 15650- 15657.

[78] Zhang H, Zhou W, Yang Y, Cheng C. 3D WO₃/BiVO₄/cobalt phosphate composites inverse opal photoanode for efficient photoelectrochemical water splitting. Small. 2017; 13 (16): 1603840.

[79] Ahn HJ, Goswami A, Riboni F, et al. Hematite photoanode with complex nanoarchitecture providing tunable gradient doping and low onset potential for photoelectrochemical water splitting. ChemSusChem. 2018; 11 (11): 1873- 1879.

[80] Chen B, Zhang Z, Baek M, Kim S, Kim W, Yong K. An antenna/spacer/reflector based Au/BiVO₄/WO₃/Au nanopatterned photoanode for plasmon-enhanced photoelectrochemical water splitting. Appl Catal B. 2018; 237: 763- 771.

[81] Dong G, Hu H, Huang X, Zhang Y, Bi Y. Rapid activation of Co₃O₄ cocatalysts with oxygen vacancies on TiO₂ photoanodes for efficient water splitting. J Mater Chem A. 2018; 6 (42): 21003- 21009.

[82] Fang Y, Xu Y, Li X, Ma Y, Wang X. Coating polymeric carbon nitride photoanodes on conductive Y:ZnO nanorod arrays for overall water splitting. Angew Chem Int Ed. 2018; 130 (31): 9897- 9901.

[83] Guan P, Bai H, Wang F, et al. Boosting water splitting performance of BiVO₄ photoanode through selective surface decoration of Ag₂S. ChemCatChem. 2018; 10 (21): 4927- 4933.

[84] Haydous F, Si W, Guzenko VA, et al. Improved photoelectrochemical water splitting of CaNbO₂N photoanodes by CoPi photodeposition and surface passivation. J Phys Chem C. 2018; 123 (2): 1059- 1068.

[85] Jeon D, Kim N, Bae S, Han Y, Ryu J. WO₃/conducting polymer heterojunction photoanodes for efficient and stable photoelectrochemical water splitting. ACS Appl Mater Interfaces. 2018; 10 (9): 8036- 8044.

[86] Jiang D, Yue Q, Tang S, Zhang L, Zhu L, Du P. A highly efficient photoelectrochemical cell using cobalt phosphidemodified nanoporous hematite photoanode for solar-driven water splitting. J Catal. 2018; 366: 275- 281.

[87] Khan I, Qurashi A, Berdiyorov G, Iqbal N, Fuji K, Yamani ZH. Single-step strategy for the fabrication of GaON/ZnO nanoarchitectured photoanode their experimental and computational photoelectrochemical water splitting. Nano Energy. 2018; 44: 23- 33.

[88] Kim JH, Jang YJ, Choi SH, et al. A multitude of modifications strategy of ZnFe₂O₄ nanorod photoanodes for enhanced photoelectrochemical water splitting activity. J Mater Chem A. 2018; 6 (26): 12693- 12700.

[89] Kölbach M, Pereira IJ, Harbauer K, et al. Revealing the performance-limiting factors in α-SnWO₄ photoanodes for solar water splitting. Chem Mater. 2018; 30 (22): 8322- 8331.

[90] Liu Y, Jiang Y, Li F, Yu F, Jiang W, Xia L. Molecular cobalt salophen catalyst-integrated BiVO₄ as stable and robust photoanodes for photoelectrochemical water splitting. J Mater Chem A. 2018; 6 (23): 10761- 10768.

[91] Lv X, Xiao X, Cao M, et al. Efficient carbon dots/NiFe-layered double hydroxide/BiVO₄ photoanodes for photoelectrochemical water splitting. Appl Surf Sci. 2018; 439: 1065- 1071.

[92] Pei L, Wang H, Wang X, Xu Z, Yan S, Zou Z. Nanostructured TaON/Ta₃N₅ as a highly efficient type-II heterojunction photoanode for photoelectrochemical water splitting. Dalton Trans. 2018; 47 (27): 8949- 8955.

[93] Wang Q, Niu T, Wang L, Huang J, She H. NiFe layered double-hydroxide nanoparticles for efficiently enhancing performance of BiVO₄ photoanode in photoelectrochemical water splitting. Chin J Catal. 2018; 39 (4): 613- 618.

[94] Wang S, Chen P, Bai Y, Yun JH, Liu G, Wang L. New BiVO₄ dual photoanodes with enriched oxygen vacancies for efficient solar-driven water splitting. Adv Mater. 2018; 30 (20): 1800486.

[95] Wang Z, Li X, Ling H, et al. 3D FTO/FTO-nanocrystal/TiO₂ composite inverse opal photoanode for efficient photoelectrochemical water splitting. Small. 2018; 14 (20): 1800395.

[96] Weng B, Grice CR, Ge J, Poudel T, Deng X, Yan Y. Barium bismuth niobate double perovskite/tungsten oxide nanosheet photoanode for high-performance photoelectrochemical water splitting. Adv Energy Mater. 2018; 8 (10): 1701655.

[97] Ye K-H, Wang Z, Li H, Yuan Y, Huang Y, Mai W. A novel CoOOH/(Ti, C)-Fe₂O₃ nanorod photoanode for photoelectrochemical water splitting. Sci China Mater. 2018; 61 (6): 887- 894.

[98] Hou H, Liu H, Gao F, et al. Packaging BiVO₄ nanoparticles in ZnO microbelts for efficient photoelectrochemical hydrogen production. Electrochim Acta. 2018; 283: 497- 508.

[99] Liang Z, Hou H, Song K, et al. Boosting the photoelectrochemical activities of all-inorganic perovskite SrTiO₃ nanofibers by engineering homo/hetero junctions. J Mater Chem A. 2018; 6 (36): 17530- 17539.

[100] Song K, Gao F, Yang W, Wang E, Wang Z, Hou H. WO₃ mesoporous nanobelts towards efficient photoelectrocatalysts for water splitting. ChemElectroChem. 2018; 5 (2): 322- 327.

[101] Zhu X, Guijarro N, Liu Y, et al. Spinel structural disorder influences solar-water-splitting performance of ZnFe₂O₄ nanorod photoanodes. Adv Mater. 2018; 30 (34): 1801612.

[102] Ma Z, Hou H, Song K, et al. Ternary WO₃/porous-BiVO₄/FeOOH hierarchical architectures: towards highly efficient photoelectrochemical performance. ChemElectroChem. 2018; 5 (23): 3660- 3667.

[103] Xu S, Fu D, Song K, et al. One-dimensional WO₃/BiVO₄ heterojunction photoanodes for efficient photoelectrochemical water splitting. Chem Eng J. 2018; 349: 368- 375.

[104] Chai X, Zhang H, Pan Q, Bian J, Chen Z, Cheng C. 3D ordered urchin-like TiO₂@Fe₂O₃ arrays photoanode for efficient photoelectrochemical water splitting. Appl Surf Sci. 2019; 470: 668- 676.

[105] Ma Z, Song K, Wang L, et al. WO₃/BiVO₄ Type-II heterojunction arrays decorated with oxygen-deficient ZnO passivation layer: a highly efficient and stable photoanode. ACS Appl Mater Interfaces. 2019; 11 (1): 889- 897.

[106] Liang Z, Hou H, Fang Z, et al. Hydrogenated TiO₂ nanorod arrays decorated with carbon quantum dots toward efficient photoelectrochemical water splitting. ACS Appl Mater Interfaces. 2019; 11 (21): 19167- 19175.

[107] Chong R, Du Y, Chang Z, et al. 2D Co-incorporated hydroxyapatite nanoarchitecture as a potential efficient oxygen evolution cocatalyst for boosting photoelectrochemical water splitting on Fe₂O₃ photoanode. Appl Catal B. 2019; 250: 224- 233.

[108] Khoomortezaei S, Abdizadeh H, Golobostanfard MR. Triple layer heterojunction WO₃/BiVO₄/BiFeO₃ porous photoanode for efficient photoelectrochemical water splitting. ACS Appl Energy Mater. 2019; 2 (9): 6428- 6439.

[109] Kim M, Lee B, Ju H, Kim JY, Kim J, Lee SW. Oxygenvacancy-introduced BaSnO_3-δ photoanodes with tunable band structures for efficient solar-driven water splitting. Adv Mater. 2019; 31 (33): 1903316.

[110] Lan Y, Liu Z, Guo Z, Ruan M, Li X, Zhao Y. 2D elongated polyhedral-like YVO₄ films: a novel photoanode for photoelectrochemical water splitting. Chem Commun. 2019; 55 (70): 10468- 10471.

[111] Lee JM, Baek JH, Gill TM, et al. A Zn:BiVO₄/Mo:BiVO₄ homojunction as an efficient photoanode for photoelectrochemical water splitting. J Mater Chem A. 2019; 7 (15): 9019- 9024.

[112] Liu J, Li J, Shao M, Wei M. Directed synthesis of SnO₂@BiVO₄/Co-Pi photoanode for highly efficient photoelectrochemical water splitting and urea oxidation. J Mater Chem A. 2019; 7 (11): 6327- 6336.

[113] Long X, Gao L, Li F, et al. Bamboo shoots shaped FeVO₄ passivated ZnO nanorods photoanode for improved charge separation/transfer process towards efficient solar water splitting. Appl Catal B. 2019; 257: 117813.

[114] Wang Y, Zhang F, Yang M, et al. Synthesis of porous MoS₂/CdSe/TiO₂ photoanodes for photoelectrochemical water splitting. Microporous Mesoporous Mater. 2019; 284: 403- 409.

[115] Yoon JW, Kim DH, Kim J-H, Jang HW, Lee J-H. NH₂-MIL-125(Ti)/TiO₂ nanorod heterojunction photoanodes for efficient photoelectrochemical water splitting. Appl Catal B. 2019; 244: 511- 518.

[116] Zhang B, Huang X, Hu H, Chou L, Bi Y. Defect-rich and ultrathin CoOOH nanolayers as highly efficient oxygen evolution catalysts for photoelectrochemical water splitting. J Mater Chem A. 2019; 7 (9): 4415- 4419.

[117] Zheng G, Wang J, Zu G, et al. Sandwich structured WO₃ nanoplatelets for highly efficient photoelectrochemical water splitting. J Mater Chem A. 2019; 7 (45): 26077- 26088.

[118] Zhou M, Liu Z, Song Q, Li X, Chen B, Liu Z. Hybrid 0D/2D edamame shaped ZnIn₂S₄ photoanode modified by Co-Pi and Pt for charge management towards efficient photoelectrochemical water splitting. Appl Catal B. 2019; 244: 188- 196.

[119] Ahmad A, Yerlikaya G, Zia-ur-Rehman, Paksoy H, Kardaş G. Enhanced photoelectrochemical water splitting using gadolinium doped titanium dioxide nanorod array photoanodes. Int J Hydrogen Energy. 2020; 45 (4): 2709- 2719.

[120] Hu X, Huang J, Zhao F, et al. Photothermal effect of carbon quantum dots enhanced photoelectrochemical water splitting of hematite photoanodes. J Mater Chem A. 2020; 8 (30): 14915- 14920.

[121] Huang M, Lei W, Wang M, et al. Large area highperformance bismuth vanadate photoanode for efficient solar water splitting. J Mater Chem A. 2020; 8 (7): 3845- 3850.

[122] Huo S, Wu Y, Zhao C, Yu F, Fang J, Yang Y. Core-shell TiO₂@Au₂₅/TiO₂ nanowire arrays photoanode for efficient photoelectrochemical full water splitting. Ind Eng Chem Res. 2020; 59 (32): 14224- 14233.

[123] Li W, Du L, Liu Q, Liu Y, Li D, Li J. Trimetallic oxyhydroxide modified 3D coral-like BiVO₄ photoanode for efficient solar water splitting. Chem Eng J. 2020; 384: 123323.

[124] Qin J, Barrio J, Peng G, et al. Direct growth of uniform carbon nitride layers with extended optical absorption towards efficient water-splitting photoanodes. Nat Commun. 2020; 11: 4701.

[125] Saxena S, Verma A, Asha K, et al. Nanostructured Ni:BiVO₄ photoanode in photoelectrochemical water splitting for hydrogen generation. Int J Hydrogen Energy. 2020; 45 (51): 26746- 26757.

[126] Sun J, Sun L, Yang X, et al. Photoanode of coupling semiconductor heterojunction and catalyst for solar PEC water splitting. Electrochim Acta. 2020; 331: 135282.

[127] Wang J, Liu C, Liu Y, Chen S. Nanoporous BiVO₄ nanoflake array photoanode for efficient photoelectrochemical water splitting. CrystEngComm. 2020; 22 (11): 1914- 1921.

[128] Wen P, Su F, Li H, et al. A Ni₂P nanocrystal cocatalyst enhanced TiO₂ photoanode towards highly efficient photoelectrochemical water splitting. Chem Eng J. 2020; 385: 123878.

[129] Xu W, Tian W, Meng L, Cao F, Li L. Ion sputtering-assisted double-side interfacial engineering for CdIn₂S₄ photoanode toward improved photoelectrochemical water splitting. Adv Mater Interfaces. 1947; 7 (6): 190.

[130] Zhang B, Chou L, Bi Y. Tuning surface electronegativity of BiVO₄ photoanodes toward high-performance water splitting. Appl Catal B. 2020; 262: 118267.

[131] Zhang S, Liu Z, Yan W, Guo Z, Ruan M. Decorating nonnoble metal plasmonic Al on a TiO₂/Cu₂O photoanode to boost performance in photoelectrochemical water splitting. Chin J Catal. 2020; 41 (12): 1884- 1893.

[132] Zhao M, Chen T, He B, et al. Photothermal effect-enhanced photoelectrochemical water splitting of a BiVO₄photoanode modified with dual-functional polyaniline. J Mater Chem A. 2020; 8 (31): 15976- 15983.

[133] Zhou S, Chen K, Huang J, et al. Preparation of heterometallic CoNi-MOFs-modified BiVO₄: a steady photoanode for improved performance in photoelectrochemical water splitting. Appl Catal B. 2020; 266: 118513.

[134] Xu W, Gao W, Meng L, Tian W, Li L. Incorporation of sulfate anions and sulfur vacancies in ZnIn₂S₄ photoanode for enhanced photoelectrochemical water splitting. Adv Energy Mater. 2021; 11 (26): 2101181.

[135] Kang Z, Lv X, Sun Z, Wang S, Zheng Y-Z, Tao X. Borate and iron hydroxide co-modified BiVO₄ photoanodes for highperformance photoelectrochemical water oxidation. Chem Eng J. 2021; 421: 129819.

[136] Gao B, Wang T, Li Y, et al. Boosting the stability and photoelectrochemical activity of a BiVO₄ photoanode through a bifunctional polymer coating. J Mater Chem A. 2021; 9 (6): 3309- 3313.

[137] Ran L, Qiu S, Zhai P, et al. Conformal macroporous inverse opal oxynitride-based photoanode for robust photoelectrochemical water splitting. J Am Chem Soc. 2021; 143 (19): 7402- 7413.

[138] Lu X, Ye K, Zhang S, et al. Amorphous type FeOOH modified defective BiVO₄ photoanodes for photoelectrochemical water oxidation. Chem Eng J. 2022; 428: 131027.

[139] Liang Z, Chen D, Xu S, et al. Synergistic promotion of photoelectrochemical water splitting efficiency of TiO₂ nanorod arrays by doping and surface modification. J Mater Chem C. 2021; 9 (36): 12263- 12272.

[140] Ge M, Li Q, Cao C, et al. One-dimensional TiO₂ nanotube photocatalysts for solar water splitting. Adv Sci. 2017; 4 (1): 1600152.

[141] Fang M, Dong G, Wei R, Ho JC. Hierarchical nanostructures: design for sustainable water splitting. Adv Energy Mater. 2017; 7 (23): 1700559.

[142] Su J, Feng X, Sloppy JD, Guo L, Grimes CA. Vertically aligned WO₃ nanowire arrays grown directly on transparent conducting oxide coated glass: synthesis and photoelectrochemical properties. Nano Lett. 2011; 11 (1): 203- 208.

[143] Li W, Da P, Zhang Y, et al. WO₃ nanoflakes for enhanced photoelectrochemical conversion. ACS Nano. 2014; 8 (11): 11770- 11777.

[144] Sivula K, Le Formal F, Grätzel M. Solar water splitting: progress using hematite (α-Fe₂O₃) photoelectrodes. ChemSusChem. 2011; 4 (4): 432- 449.

[145] Wang Y, Tian W, Chen C, Xu W, Li L. Tungsten trioxide nanostructures for photoelectrochemical water splitting: material engineering and charge carrier dynamic manipulation. Adv Funct Mater. 2019; 29 (23): 1809036.

[146] Zhang H, Cheng C. Three-dimensional FTO/TiO₂/BiVO₄ composite inverse opals photoanode with excellent photoelectrochemical performance. ACS Energy Lett. 2017; 2 (4): 813- 821.

[147] Yan K, Qiu Y, Xiao S, et al. Self-driven hematite-based photoelectrochemical water splitting cells with threedimensional nanobowl heterojunction and highphotovoltage perovskite solar cells. Mater Today Energy. 2017; 6: 128- 135.

[148] Qiu Y, Leung S-F, Wei Z, et al. Enhanced charge collection for splitting of water enabled by an engineered threedimensional nanospike array. J Phys Chem C. 2014; 118 (39): 22465- 22472.

[149] Han H, Riboni F, Karlicky F, et al. α-Fe₂O₃/TiO₂3D hierarchical nanostructures for enhanced photoelectrochemical water splitting. Nanoscale. 2017; 9 (1): 134- 142.

[150] Su F-Y, Zhang W-D. Fabrication and photoelectrochemical property of In₂O₃/ZnO composite nanotube arrays using ZnO nanorods as self-sacrificing templates. Mater Lett. 2018; 211: 65- 68.

[151] Yao C, Wei B, Ma H, et al. Enhanced photoelectrochemical performance of hydrogenated ZnO hierarchical nanorod arrays. J Power Sources. 2013; 237: 295- 299.

[152] Miao J, Yang HB, Khoo SY, Liu B. Electrochemical fabrication of ZnO-CdSe core-shell nanorod arrays for efficient photoelectrochemical water splitting. Nanoscale. 2013; 5 (22): 11118- 11124.

[153] Seabold JA, Choi K-S. Efficient and stable photo-oxidation of water by a bismuth vanadate photoanode coupled with an iron oxyhydroxide oxygen evolution catalyst. J Am Chem Soc. 2012; 134 (4): 2186- 2192.

[154] Park Y, Kang D, Choi K-S. Marked enhancement in electron-hole separation achieved in the low bias region using electrochemically prepared Mo-doped BiVO₄ photoanodes. Phys Chem Chem Phys. 2014; 16 (3): 1238- 1246.

[155] McDonald KJ, Choi K-S. A new electrochemical synthesis route for a BiOI electrode and its conversion to a highly efficient porous BiVO₄ photoanode for solar water oxidation. Energy Environ Sci. 2012; 5 (9): 8553- 8557.

[156] Scherrer B, Li T, Tsyganok A, et al. Defect segregation and its effect on the photoelectrochemical properties of Ti-doped hematite photoanodes for solar water splitting. Chem Mater. 2020; 32 (3): 1031- 1040.

[157] Murcia-López S, Fàbrega C, Monllor-Satoca D, et al. Tailoring multilayered BiVO₄ photoanodes by pulsed laser deposition for water splitting. ACS Appl Mater Interfaces. 2016; 8 (6): 4076- 4085.

[158] Bassi PS, Xi F, Kölbach M, et al. Pulsed laser deposited Fe₂TiO₅ photoanodes for photoelectrochemical water oxidation. J Phys Chem C. 2020; 124 (37): 19911- 19921.

[159] Wang X, Yushin G. Chemical vapor deposition and atomic layer deposition for advanced lithium ion batteries and supercapacitors. Energy Environ Sci. 2015; 8 (7): 1889- 1904.

[160] Alarcón-Lladó E, Chen L, Hettick M, et al. BiVO₄thin film photoanodes grown by chemical vapor deposition. Phys Chem Chem Phys. 2014; 16 (4): 1651- 1657.

[161] Cheng C, Ren W, Zhang H. 3D TiO₂/SnO₂ hierarchically branched nanowires on transparent FTO substrate as photoanode for efficient water splitting. Nano Energy. 2014; 5: 132- 138.

[162] Bai S, Tian K, Meng JC, et al. Reduced graphene oxide decorated SnO₂/BiVO₄ photoanode for photoelectrochemical water splitting. J Alloys Compd. 2021; 855: 156780.

[163] Abbas Y, Zuhra Z, Akhtar N, Ali S, Gong JR. Single-step fabrication of visible-light-active ZnO-GaN:ZnO branched nanowire array photoanodes for efficient water splitting. ACS Appl Energy Mater. 2018; 1 (8): 3529- 3536.

[164] Qian L, Wang C, Chen A, Yang H. BiOI nanosheets grown by chemical vapor deposition and its conversion to highly efficient BiVO₄ photoanode. Chin J Chem. 2017; 35 (1): 30- 34.

[165] Wang CW, Yang S, Jiang HB, Yang H. Chemical vapor deposition of FeOCl nanosheet arrays and their conversion to porous α-Fe₂O₃ photoanodes for photoelectrochemical water splitting. Chem Eur J. 2015; 21 (50): 18024- 18028.

[166] Gardecka AJ, Bishop C, Lee D, et al. High efficiency water splitting photoanodes composed of nano-structured anataserutile TiO₂ heterojunctions by pulsed-pressure MOCVD. Appl Catal B. 2018; 224: 904- 911.

[167] Regue M, Sibby S, Ahmet IY, et al. TiO₂ photoanodes with exposed {0 1 0} facets grown by aerosol-assisted chemical vapor deposition of a titanium oxo/alkoxy cluster. J Mater Chem A. 2019; 7 (32): 19161- 19172.

[168] Khan HR, Aamir M, Akram B, et al. Superior visible-light assisted water splitting performance by Fe incorporated ZnO photoanodes. Mater Res Bull. 2020; 122: 110627.

[169] Coll M, Napari M. Atomic layer deposition of functional multicomponent oxides. APL Mater. 2019; 7 (11): 110901.

[170] Gao Y, Zandi O, Hamann TW. Atomic layer stack depositionannealing synthesis of CuWO₄. J Mater Chem A. 2016; 4 (8): 2826- 2830.

[171] Bielinski AR, Lee S, Brancho JJ, et al. Atomic layer deposition of bismuth vanadate core-shell nanowire photoanodes. Chem Mater. 2019; 31 (9): 3221- 3227.

[172] Mozumder MS, Mourad A-HI, Pervez H, Surkatti R. Recent developments in multifunctional coatings for solar panel applications: a review. Sol Energy Mater Sol Cells. 2019; 189: 75- 102.

[173] Rout T, Bera S, Udayabhanu G, Narayan R. Methodologies of application of sol-gel based solution onto substrate: a review. J Coat Sci Technol. 2016; 3 (1): 9- 22.

[174] Chen Q, Li J, Zhou B, et al. Preparation of well-aligned WO₃ nanoflake arrays vertically grown on tungsten substrate as photoanode for photoelectrochemical water splitting. Electrochem Commun. 2012; 20: 153- 156.

[175] Wang L, Zhou X, Nguyen NT, Hwang I, Schmuki P. Strongly enhanced water splitting performance of Ta₃N₅ nanotube photoanodes with subnitrides. Adv Mater. 2016; 28 (12): 2432- 2438.

[176] Lee C-Y, Taylor AC, Beirne S, Wallace GG. 3D-printed conical arrays of TiO₂ electrodes for enhanced photoelectrochemical water splitting. Adv Energy Mater. 2017; 7 (21): 1701060.

[177] Nishimae S, Mishima Y, Nishiyama H, et al. Fabrication of BaTaO₂N thin films by interfacial reactions of BaCO₃/Ta₃N₅ layers on a Ta substrate and resulting high photoanode efficiencies during water splitting. Solar RRL. 2020; 4 (4): 1900542.

[178] Lu X, Zheng D, Zhang P, Liang C, Liu P, Tong Y. Facile synthesis of free-standing CeO₂ nanorods for photoelectrochemical applications. Chem Commun. 2010; 46 (41): 7721- 7723.

[179] Smith YR, Sarma B, Mohanty SK, Misra M. Single-step anodization for synthesis of hierarchical TiO₂ nanotube arrays on foil and wire substrate for enhanced photoelectrochemical water splitting. Int J Hydrogen Energy. 2013; 38 (5): 2062- 2069.

[180] Seo J, Moriya Y, Kodera M, et al. Photoelectrochemical water splitting on particulate ANbO₂N (A=Ba, Sr) photoanodes prepared from perovskite-type ANbO₃. Chem Mater. 2016; 28 (19): 6869- 6876.

[181] Hejazi S, Nguyen NT, Mazare A, Schmuki P. Aminated TiO₂ nanotubes as a photoelectrochemical water splitting photoanode. Catal Today. 2017; 281: 189- 197.

[182] Li L, Zhao X, Pan D, Li G. Nanotube array-like WO₃/W photoanode fabricated by electrochemical anodization for photoelectrocatalytic overall water splitting. Chin J Catal. 2017; 38 (12): 2132- 2140.

[183] Matarrese R, Nova I, Li Bassi A, Casari CS, Russo V, Palmas S. Preparation and optimization of TiO₂ photoanodes fabricated by pulsed laser deposition for photoelectrochemical water splitting. J Solid State Electrochem. 2017; 21 (11): 3139- 3154.

[184] Momeni MM, Ghayeb Y, Shafiei M. Preparation and characterization of CrFeWTiO₂ photoanodes and their photoelectrochemical activities for water splitting. Dalton Trans. 2017; 46 (37): 12527- 12536.

[185] Zhong M, Hisatomi T, Sasaki Y, et al. Highly active GaNstabilized Ta₃N₅ thin-film photoanode for solar water oxidation. Angew Chem Int Ed. 2017; 129 (17): 4817- 4821.

[186] Bialuschewski D, Hoppius JS, Frohnhoven R, et al. Lasertextured metal substrates as photoanodes for enhanced PEC water splitting reactions. Adv Eng Mater. 2018; 20 (9): 1800167.

[187] Dong Z, Ding D, Li T, Ning C. Ni-doped TiO₂ nanotubes photoanode for enhanced photoelectrochemical water splitting. Appl Surf Sci. 2018; 443: 321- 328.

[188] Dong Z, Ding D, Li T, Ning C. Black Si-doped TiO₂ nanotube photoanode for high-efficiency photoelectrochemical water splitting. RSC Adv. 2018; 8 (11): 5652- 5660.

[189] Dong Z, Ding D, Li T, Ning C. NaBH₄ reduction of TiSiO nanotubes photoanode for high-efficiency photoelectrochemical water splitting. Int J Hydrogen Energy. 2018; 43 (31): 14183- 14192.

[190] Liu C, Wang F, Zhang J, et al. Efficient photoelectrochemical water splitting by g-C₃N₄/TiO₂ nanotube array heterostructures. Nano-Micro Lett. 2018; 10 (2): 37.

[191] Nurlaela E, Sasaki Y, Nakabayashi M, Shibata N, Yamada T, Domen K. Towards zero bias photoelectrochemical water splitting: onset potential improvement on a Mg:GaN modified-Ta₃N₅ photoanode. J Mater Chem A. 2018; 6 (31): 15265- 15273.

[192] Sharifi T, Ghayeb Y, Mohammadi T, Momeni MM. Enhanced photoelectrochemical water splitting of CrTiO₂ nanotube photoanodes by the decoration of their surface via the photodeposition of Ag and Au. Dalton Trans. 2018; 47 (33): 11593- 11604.

[193] Wang L, Zhang B, Rui Q. Plasma-induced vacancy defects in oxygen evolution cocatalysts on Ta₃N₅ photoanodes promoting solar water splitting. ACS Catal. 2018; 8 (11): 10564- 10572.

[194] Zhu H, Zhao M, Zhou J, et al. Surface states as electron transfer pathway enhanced charge separation in TiO₂ nanotube water splitting photoanodes. Appl Catal B. 2018; 234: 100- 108.

[195] Chen R, Zhen C, Yang Y, et al. Boosting photoelectrochemical water splitting performance of Ta₃N₅ nanorod array photoanodes by forming a dual co-catalyst shell. Nano Energy. 2019; 59: 683- 688.

[196] Dong Z, Ding D, Li T, Ning C. Facile preparation of Ti³⁺/Ni codoped TiO₂ nanotubes photoanode for efficient photoelectrochemical water splitting. Appl Surf Sci. 2019; 480: 219- 228.

[197] Lin J, Liu Y, Liu Y, et al. SnS₂ Nanosheets/H-TiO₂ nanotube arrays as a Type II heterojunctioned photoanode for photoelectrochemical water splitting. ChemSusChem. 2019; 12 (5): 961- 967.

[198] Seo J, Nakabayashi M, Hisatomi T, Shibata N, Minegishi T, Domen K. Solar-driven water splitting over a BaTaO₂N photoanode enhanced by annealing in argon. ACS Appl Energy Mater. 2019; 2 (8): 5777- 5784.

[199] Soltani T, Tayyebi A, Hong H, Mirfasih MH, Lee B-K. A novel growth control of nanoplates WO₃ photoanodes with dual oxygen and tungsten vacancies for efficient photoelectrochemical water splitting performance. Sol Energy Mater Sol Cells. 2019; 191: 39- 49.

[200] Ma Z, Hou H, Song K, et al. Engineering oxygen vacancies by one-step growth of distributed homojunctions to enhance charge separation for efficient photoelectrochemical water splitting. Chem Eng J. 2020; 379: 122266.

[201] Barczuk PJ, Noworyta KR, Dolata M, Jakubow-Piotrowska K, Augustynski J. Visible-light activation of low-cost rutile TiO₂ photoanodes for photoelectrochemical water splitting. Sol Energy Mater Sol Cells. 2020; 208: 110424.

[202] Zhang X, Guo H, Dong G, Zhang Y, Lu G, Bi Y. Homostructural Ta₃N₅ nanotube/nanoparticle photoanodes for highly efficient solar-driven water splitting. Appl Catal B. 2020; 277: 119217.

[203] Zhao Y, Liu G, Wang H, et al. Interface engineering with an AlOx dielectric layer enabling an ultrastable Ta₃N₅ photoanode for photoelectrochemical water oxidation. J Mater Chem A. 2021; 9 (18): 11285- 11290.

[204] Chen Y, Xia H, Feng X, et al. Synergy of porous structure and cation doping in Ta₃N₅ photoanode towards improved photoelectrochemical water oxidation. J Energy Chem. 2021; 52: 343- 350.

[205] Zhao Y, Xie H, Shi W, Wang H, Shao C, Li C. Unravelling the essential difference between TiO and AlO interface layers on Ta₃N₅ photoanode for photoelectrochemical water oxidation. J Energy Chem. 2022; 64: 33- 37.

[206] Tayebi M, Masoumi Z, Lee B-K. Ultrasonically prepared photocatalyst of W/WO₃ nanoplates with WS₂ nanosheets as 2D material for improving photoelectrochemical water splitting. Ultrason Sonochem. 2021; 70: 105339.

[207] Soltani T, Tayyebi A, Lee B-K. Sonochemical-driven ultrafast facile synthesis of WO₃ nanoplates with controllable morphology and oxygen vacancies for efficient photoelectrochemical water splitting. Ultrason Sonochem. 2019; 50: 230- 238.

[208] Ma Z, Song K, Zhang T, et al. MXenes-like multilayered tungsten oxide architectures for efficient photoelectrochemical water splitting. Chem Eng J. 2022; 430: 132936.

[209] Feng X, Latempa TJ, Basham JI, Mor GK, Varghese OK, Grimes CA. Ta₃N₅ nanotube arrays for visible light water photoelectrolysis. Nano Lett. 2010; 10 (3): 948- 952.

[210] Su Z, Grigorescu S, Wang L, Lee K, Schmuki P. Fast fabrication of Ta₂O₅ nanotube arrays and their conversion to Ta₃N₅ for efficient solar driven water splitting. Electrochem commun. 2015; 50: 15- 19.

[211] Li Y, Zhang L, Torres-Pardo A, et al. Cobalt phosphatemodified barium-doped tantalum nitride nanorod photoanode with 1.5% solar energy conversion efficiency. Nat Commun. 2013; 4: 2566.

[212] Wang L, Dionigi F, Nguyen NT, et al. Tantalum nitride nanorod arrays: introducing Ni-Fe layered double hydroxides as a cocatalyst strongly stabilizing photoanodes in water splitting. Chem Mater. 2015; 27 (7): 2360- 2366.

[213] Zhen C, Wang L, Liu G, Lu GQ, Cheng H-M. Template-free synthesis of Ta₃N₅ nanorod arrays for efficient photoelectrochemical water splitting. Chem Commun. 2013; 49 (29): 3019- 3021.

[214] Xiang Y, Zhang B, Liu J, et al. A one-step synthesis of a Ta₃N₅ nanorod photoanode from Ta plates and NH₄Cl powder for photoelectrochemical water oxidation. Chem Commun. 2020; 56 (79): 11843- 11846.

[215] Higashi M, Domen K, Abe R. Fabrication of an efficient BaTaO₂N photoanode harvesting a wide range of visible light for water splitting. J Am Chem Soc. 2013; 135 (28): 10238- 10241.

[216] Ueda K, Minegishi T, Clune J, et al. Photoelectrochemical oxidation of water using BaTaO₂N photoanodes prepared by particle transfer method. J Am Chem Soc. 2015; 137 (6): 2227- 2230.

[217] Wang C, Hisatomi T, Minegishi T, et al. Synthesis of nanostructured BaTaO₂N thin films as photoanodes for solar water splitting. J Phys Chem C. 2016; 120 (29): 15758- 15764.

[218] Jun H, Im B, Kim JY, et al. Photoelectrochemical water splitting over ordered honeycomb hematite electrodes stabilized by alumina shielding. Energy Environ Sci. 2012; 5 (4): 6375- 6382.

[219] Prakasam HE, Varghese OK, Paulose M, Mor GK, Grimes CA. Synthesis and photoelectrochemical properties of nanoporous iron (III) oxide by potentiostatic anodization. Nanotechnology. 2006; 17 (17): 4285- 4291.

[220] Wang L, Nguyen NT, Zhang Y, Bi Y, Schmuki P. Enhanced solar water splitting by swift charge separation in Au/FeOOH sandwiched single-crystalline Fe₂O₃ nanoflake photoelectrodes. ChemSusChem. 2017; 10 (13): 2720- 2727.

[221] Wang L, Hu H, Nguyen NT, Zhang Y, Schmuki P, Bi Y. Plasmon-induced hole-depletion layer on hematite nanoflake photoanodes for highly efficient solar water splitting. Nano Energy. 2017; 35: 171- 178.

[222] Wang L, Nakajima T, Zhang Y. Simultaneous reduction of surface, bulk, and interface recombination for Au nanoparticle-embedded hematite nanorod photoanodes toward efficient water splitting. J Mater Chem A. 2019; 7 (10): 5258- 5265.

[223] Li G, Wang W, Yang W, et al. GaN-based light-emitting diodes on various substrates: a critical review. Rep Prog Phys. 2016; 79 (5): 056501.

[224] Ebaid M, Kang J-H, Ryu S-W. Controlled synthesis of GaNbased nanowires for photoelectrochemical water splitting applications. Semicond Sci Technol. 2017; 32 (1): 013001.

[225] Zhong M, Li Y, Yamada I, Delaunay JJ. ZnO-ZnGa₂O₄ coreshell nanowire array for stable photoelectrochemical water splitting. Nanoscale. 2012; 4 (5): 1509- 1514.

[226] Zhong M, Sato Y, Kurniawan M, et al. ZnO dense nanowire array on a film structure in a single crystal domain texture for optical and photoelectrochemical applications. Nanotechnology. 2012; 23 (49): 495602.

[227] Ryu S-W, Zhang Y, Leung B, Yerino C, Han J. Improved photoelectrochemical water splitting efficiency of nanoporous GaN photoanode. Semicond Sci Technol. 2012; 27 (1): 015014.

[228] Caccamo L, Hartmann J, Fàbrega C, et al. Band engineered epitaxial 3D GaN-InGaN core-shell rod arrays as an advanced photoanode for visible-light-driven water splitting. ACS Appl Mater Interfaces. 2014; 6 (4): 2235- 2240.

[229] Kim SH, Ebaid M, Kang J-H, Ryu S-W. Improved efficiency and stability of GaN photoanode in photoelectrochemical water splitting by NiO cocatalyst. Appl Surf Sci. 2014; 305: 638- 641.

[230] Ebaid M, Kang J-H, Lim S-H, Cho Y-H, Ryu S-W. Towards highly efficient photoanodes: the role of carrier dynamics on the photoelectrochemical performance of InGaN/GaN multiple quantum well coaxial nanowires. RSC Adv. 2015; 5 (30): 23303- 23310.

[231] Ebaid M, Kang J-H, Lim S-H, et al. Enhanced solar hydrogen generation of high density, high aspect ratio, coaxial InGaN/GaN multi-quantum well nanowires. Nano Energy. 2015; 12: 215- 223.

[232] Grave DA, Dotan H, Levy Y, et al. Heteroepitaxial hematite photoanodes as a model system for solar water splitting. J Mater Chem A. 2016; 4 (8): 3052- 3060.

[233] Kamimura J, Bogdanoff P, Abdi FF, et al. Photoelectrochemical properties of GaN photoanodes with cobalt phosphate catalyst for solar water splitting in neutral electrolyte. J Phys Chem C. 2017; 121 (23): 12540- 12545.

[234] Alqahtani M, Sathasivam S, Alhassan A, et al. InGaN/GaN multiple quantum well photoanode modified with cobalt oxide for water oxidation. ACS Appl Energy Mater. 2018; 1 (11): 6417- 6424.

[235] Butson J, Narangari PR, Karuturi SK, et al. Photoelectrochemical studies of InGaN/GaN MQW photoanodes. Nanotechnology. 2018; 29 (4): 045403.

[236] Hassan MA, Kang J-H, Johar MA, Ha J-S, Ryu S-W. Highperformance ZnS/GaN heterostructure photoanode for photoelectrochemical water splitting applicatio. Acta Materialia. 2018; 146: 171- 175.

[237] Kim YJ, Lee GJ, Kim S, et al. Efficient light absorption by GaN truncated nanocones for high performance water splitting applications. ACS Appl Mater Interfaces. 2018; 10 (34): 28672- 28678.

[238] Hassan MA, Kim MW, Johar MA, Waseem A, Kwon MK, Ryu SW. Transferred monolayer MoS₂ onto GaN for heterostructure photoanode: toward stable and efficient photoelectrochemical water splitting. Sci Rep. 2019; 9 (1): 20141.

[239] Higashi T, Nishiyama H, Suzuki Y, et al. Transparent Ta₃N₅ photoanodes for efficient oxygen evolution toward the development of tandem cells. Angew Chem Int Ed. 2019; 131 (8): 2322- 2326.

[240] Li Z, Xu Z, Dongjing Li Li, Wu A, Ruan R. A nanoporous GaN photoelectrode on patterned sapphire substrates for high-efficiency photoelectrochemical water splitting. J Alloys Compd. 2019; 803: 748- 756.

[241] Patil SS, Johar MA, Hassan MA, Patil DR, Ryu S-W. Enhanced photoelectrocatalytic water oxidation using CoPi modified GaN/MWCNTs composite photoanodes. Sol Energy. 2019; 178: 125- 132.

[242] Tamura S, Ueno K, Hato K. Niobium oxynitride prepared by thermal NH₃ nitridation as a photoanode material for solar water splitting. Mater Res Bull. 2019; 112: 221- 225.

[243] Alizadeh M, Tong GB, Qadir KW, Mehmood MS, Rasuli R. Cu₂O/InGaN heterojunction thin films with enhanced photoelectrochemical activity for solar water splitting. Renew Energy. 2020; 156: 602- 609.

[244] Ma Z, Piętak K, Piątek J, et al. Semi-transparent quaternary oxynitride photoanodes on GaN underlayers. Chem Commun. 2020; 56 (86): 13193- 13196.

[245] Wang H-K, Kogularasu S, Liao P-H, Yao Y-T, Lee M-L, Sheu J-K. NiOx nanoparticles as active water splitting catalysts for the improved photostability of a n-GaN photoanode. Sol Energy Mater Sol Cells. 2020; 216: 110723.

[246] Cao D, Xiao H, Yang X, Ma X. Preparation and improved photoelectrochemical properties of InGaN/GaN photoanode with mesoporous GaN distributed bragg reflectors. J Alloys Compd. 2021; 853: 157201.

[247] Pal Y, Anthony Raja M, Madhumitha M, Nikita A, Neethu A. Fabrication and characterization of gallium nitride thin film deposited on a sapphire substrate for photoelectrochemical water splitting applications. Optik. 2021; 226: 165410.

[248] Patil SS, Johar MA, Hassan MA, et al. Synergic effect of ZnO nanostructures and cobalt phosphate co-catalyst on photoelectrochemical properties of GaN. Mater Chem Phys. 2021; 260: 124141.

[249] Fujii K, Karasawa T, Ohkawa K. Hydrogen gas generation by splitting aqueous water using n-type GaN photoelectrode with anodic oxidation. Jpn J Appl Phys. 2005; 44 (4L): L543- L545.

[250] Yang C, Liu L, Zhu S, et al. GaN with laterally aligned nanopores to enhance the water splitting. J Phys Chem C. 2017; 121 (13): 7331- 7336.

[251] Peng K-Q, Wang X, Li L, Hu Y, Lee S-T. Silicon nanowires for advanced energy conversion and storage. Nano Today. 2013; 8 (1): 75- 97.

[252] Chandrasekaran S, Nann T, Voelcker NH. Nanostructured silicon photoelectrodes for solar water electrolysis. Nano Energy. 2015; 17: 308- 322.

[253] Fan R, Mi Z, Shen M. Silicon based photoelectrodes for photoelectrochemical water splitting. Opt Express. 2019; 27 (4): A51- A80.

[254] Yu X, Yang P, Chen S, Zhang M, Shi G. NiFe alloy protected silicon photoanode for efficient water splitting. Adv Energy Mater. 2016; 7 (6): 1601805.

[255] Qi X, She G, Huang X, et al. High-performance n-Si/α-Fe₂O₃ core/shell nanowire array photoanode towards photoelectrochemical water splitting. Nanoscale. 2014; 6 (6): 3182- 3189.

[256] Sheng W, Sun B, Shi T, Tan X, Peng Z, Liao G. Quantum dotsensitized hierarchical micro/nanowire architecture for photoelectrochemical water splitting. ACS Nano. 2014; 8 (7): 7163- 7169.

[257] Narkeviciute I, Chakthranont P, Mackus AJM, et al. Tandem core-shell Si-Ta₃N₅ photoanodes for photoelectrochemical water splitting. Nano Lett. 2016; 16 (12): 7565- 7572.

[258] Pavlenko M, Siuzdak K, Coy E, Jancelewicz M, Jurga S, Iatsunskyi I. Silicon/TiO₂ core-shell nanopillar photoanodes for enhanced photoelectrochemical water oxidation. Int J Hydrogen Energy. 2017; 42 (51): 30076- 30085.

[259] Wu F, Liao Q, Cao F, Li L, Zhang Y. Non-noble bimetallic NiMoO₄ nanosheets integrated Si photoanodes for highly efficient and stable solar water splitting. Nano Energy. 2017; 34: 8- 14.

[260] Yang J, Cooper JK, Toma FM, et al. A multifunctional biphasic water splitting catalyst tailored for integration with high-performance semiconductor photoanodes. Nat Mater. 2017; 16 (3): 335- 341.

[261] Jeong K, Deshmukh PR, Park J, Sohn Y, Shin WG. ZnO-TiO₂ core-shell nanowires: a sustainable photoanode for enhanced photoelectrochemical water splitting. ACS Sustainable Chem Eng. 2018; 6 (5): 6518- 6526.

[262] Li C, Huang M, Zhong Y, Zhang L, Xiao Y, Zhu H. Highly efficient NiFe nanoparticle decorated Si photoanode for photoelectrochemical water oxidation. Chem Mater. 2018; 31 (1): 171- 178.

[263] Oh K, Mériadec C, Lassalle-Kaiser B, et al. Elucidating the performance and unexpected stability of partially coated water-splitting silicon photoanodes. Energy Environ Sci. 2018; 11 (9): 2590- 2599.

[264] Zhao J, Gill TM, Zheng X. Enabling silicon photoanodes for efficient solar water splitting by electroless-deposited nickel. Nano Res. 2018; 11 (6): 3499- 3508.

[265] Huang G, Fan R, Zhou X, et al. A porous Ni-O/Ni/Si photoanode for stable and efficient photoelectrochemical water splitting. Chem Commun. 2019; 55 (3): 377- 380.

[266] Li Y, Xu G, Zhu X, et al. A hierarchical dual-phase photoetching template route to assembling functional layers on si photoanode with tunable nanostructures for efficient water splitting. Appl Catal B. 2019; 259: 118115.

[267] Zhou Z, Wu S, Li L, Li L, Li X. Regulating the silicon/hematite microwire photoanode by the conformal Al₂O₃ intermediate layer for water splitting. ACS Appl Mater Interfaces. 2019; 11 (6): 5978- 5988.

[268] Anbarasan N, Sadhasivam S, Mukilan M, Jeganathan K. GaN nanowires grown by halide chemical vapour deposition as photoanodes for photo-electrochemical water oxidation reactions. Nanotechnology. 2020; 31 (42): 425405.

[269] Chuang C-H, Lai Y-Y, Hou C-H, Cheng Y-J. Annealed polycrystalline TiO₂ interlayer of the n-Si/TiO₂/Ni photoanode for efficient photoelectrochemical water splitting. ACS Appl Energy Mater. 2020; 3 (4): 3902- 3908.

[270] Chen H, Wang P, Wang X, et al. 3D InGaN nanowire arrays on oblique pyramid-textured Si (311) for light trapping and solar water splitting enhancement. Nano Energy. 2021; 83: 105768.

[271] Olivares F, Segura del Río R, Reyes J, et al. Enhanced photoconversion efficiency of hybrid TiO₂/nox-MWCNT/Si photoanode for water splitting in neutral medium. Mater Lett. 2021; 285: 129128.

[272] Boddula R, Xie G, Guo B, Gong JR. Role of transition-metal electrocatalysts for oxygen evolution with Si-based photoanodes. Chin J Catal. 2021; 42 (8): 1387- 1394.

[273] Lin J, Zhang Z, Chai J, et al. Highly efficient InGaN nanorods photoelectrode by constructing Z-scheme charge transfer system for unbiased water splitting. Small. 2021; 17 (3): 2006666.

[274] Hassan MA, Johar MA, Yu SY, Ryu S-W. Facile synthesis of well-aligned ZnO nanowires on various substrates by MOCVD for enhanced photoelectrochemical water-splitting performance. ACS Sustainable Chem Eng. 2018; 6 (12): 16047- 16054.

[275] Jian J, Sun J. A review of recent progress on silicon carbide for photoelectrochemical water splitting. Solar RRL. 2020; 4 (7): 2000111.

[276] Tuci G, Liu Y, Rossin A, et al. Porous silicon carbide (SiC): a chance for improving catalysts or just another active-phase carrier? Chem Rev. 2021; 121 (17): 10559- 10665.

[277] Li H, Shang H, Shi Y, et al. Atomically manipulated proton transfer energizes water oxidation on silicon carbide photoanodes. J Mater Chem A. 2018; 6 (47): 24358- 24366.

[278] Chen S, Zhao L, Wang L, Gao F, Yang W. Single-crystal Ndoped SiC nanochannel array photoanode for efficient photoelectrochemical water splitting. J Mater Chem C. 2019; 7 (11): 3173- 3180.

[279] Jian J, Shi Y, Ekeroth S, et al. A nanostructured NiO/cubic SiC p-n heterojunction photoanode for enhanced solar water splitting. J Mater Chem A. 2019; 7 (9): 4721- 4728.

[280] Jian J, Shi Y, Syväjärvi M, Yakimova R, Sun J. Cubic SiC photoanode coupling with Ni:FeOOH oxygen-evolution cocatalyst for sustainable photoelectrochemical water oxidation. Solar RRL. 2019; 4 (1): 1900364.

[281] Li H, Shi Y, Shang H, et al. Atomic-scale tuning of Graphene/Cubic SiC schottky junction for stable low-bias photoelectrochemical solar-to-fuel conversi. ACS Nano. 2020; 14 (4): 4905- 4915.

[282] Wei Y, Ke L, Kong J, et al. Enhanced photoelectrochemical water-splitting effect with a bent ZnO nanorod photo anode decorated with Ag nanoparticles. Nanotechnology. 2012; 23 (23): 235401.

[283] Hou Y, Zuo F, Dagg AP, Liu J, Feng P. Branched WO₃ nanosheet array with layered C₃N₄ heterojunctions and CoO_x nanoparticles as a flexible photoanode for efficient photoelectrochemical water oxidation. Adv Mater. 2014; 26 (29): 5043- 5049.

[284] Thakur A, Kumar P, Mouli Thalluri S, Sinha RK, Devi P. Flexible polypyrrole activated micro-porous paper-based photoanode for photoelectrochemical water splitting. Int J Hydrogen Energy. 2021; 46 (12): 8444- 8453.

[285] Singh S, Khare N. Flexible PVDF/Cu/PVDF-NaNbO₃ photoanode with ferroelectric properties: an efficient tuning of photoelectrochemical water splitting with electric field polarization and piezophototronic effect. Nano Energy. 2017; 42: 173- 180.

[286] Quynh LT, Van CN, Tzeng WY, et al. Flexible heteroepitaxy photoelectrode for photo-electrochemical water splitting. ACS Appl Energy Mater. 2018; 1 (8): 3900- 3907.

[287] Seok Jo H, Samuel E, Kwon H-J, et al. Highly flexible transparent substrate-free photoanodes using ZnO nanowires on nickel microfibers. Chem Eng J. 2019; 363: 13- 22.

[288] Shin H, Kim T, Seo I, et al. Fabrication of scalable and flexible bio-photoanodes by electrospraying thylakoid/graphene oxide composites. Appl Surf Sci. 2019; 481: 1- 9.

[289] Chen J, Zhang J, Ye M, et al. Flexible TiO₂/Au thin films with greatly enhanced photocurrents for photoelectrochemical water splitting. J Alloys Compd. 2020; 815: 152471.

[290] Vadla SS, Bandyopadhyay P, John S, Ghosh P, Roy SC. TiO₂ nanotube arrays on flexible kapton substrates for photoelectrochemical solar energy conversion. ACS Appl Nano Mater. 2020; 3 (12): 11715- 11724.

[291] Zhang J, Chen J, Ye M, et al. Large photoelectrochemical activity of flexible TiO₂/SrRuO₃ oxide heterojunction. Appl Surf Sci. 2020; 504: 144544.

[292] Shao PW, Siao YS, Lai YH, et al. Flexible BiVO₄/WO₃/ITO/Muscovite heterostructure for visible-light photoelectrochemical photoelectrode. ACS Appl Mater Interfaces. 2021; 13 (18): 21186- 21193.

[293] Lee J, Lee S, Seo S, et al. Bendable BiVO₄-based photoanodes on a metal substrate realized through template engineering for photoelectrochemical water splitting. ACS Appl Mater Interfaces. 2021; 13 (14): 16478- 16484.

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