Abstract
Through the use of XPS and controlled Ar+ etching, the surface composition and oxide species of tantalum oxides (TaO x ), which were electrodeposited on glassy carbon electrodes by cyclic voltammetric and constant-potential electrolyses, are quantified along the depth profile. Electrodeposition exhibits efficacy in depositing TaO x with a distribution of various TaO x : TaO, TaO2, and Ta2O5. The distribution gradient from the outer surface of TaO x is such that Ta2O5 > TaO2 > TaO. TaO is found to be the dominant species in the underlying layer of TaO x . Such a unique structure of the electrode surface is analogous to that of nanoparticles with a core–shell structure, with the core being suboxides and the surface being that of the saturated pentoxide, Ta2O5. The electrochemically induced nonhydrolytic condensation route is proposed to be capable of producing TaO x with a distribution gradient of Ta2O5, TaO2, and TaO in the depth direction.
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Oh T, Kim JY, Shin Y, Engelhard M, Weil KS (2011) Effects of tungsten oxide addition on the electrochemical performance of nanoscale tantalum oxide-based electrocatalysts for proton exchange membrane (PEM) fuel cells. J Power Sources 196(15):6099–6103
Kim JY, Oh T-K, Shin Y, Bonnett J, Weil KS (2011) A novel non-platinum group electrocatalyst for PEM fuel cell application. Int J Hydrogen Energy 36(7):4557–4564
Ushikubo T (2000) Recent topics of research and development of catalysis by niobium and tantalum oxides. Catal Today 57(3–4):331–338
Chen Y, Fierro JLG, Tanaka T, Wachs IE (2003) Supported tantalum oxide catalysts: synthesis, physical characterization, and methanol oxidation chemical probe reaction. J Phys Chem B 107(22):5243–5250
Baturina OA, Garsany Y, Zega TJ, Stroud RM, Schull T, Swider-Lyons KE (2008) Oxygen reduction reaction on platinum/tantalum oxide electrocatalysts for PEM fuel cells. J Electrochem Soc 155(12):B1314–B1321
Garsany Y, Epshteyn A, Purdy AP, More KL, Swider-Lyons KE (2010) High-activity, durable oxygen reduction electrocatalyst: nanoscale composite of platinum−tantalum oxyphosphate on vulcan carbon. J Phys Chem Lett 1(13):1977–1981
Awaludin Z, Suzuki M, Masud J, Okajima T, Ohsaka T (2011) Enhanced electrocatalysis of oxygen reduction on Pt/TaO x /GC. J Phys Chem C 115(51):25557–25567
Ferdousi BN, Mominul Islam M, Okajima T, Mao L, Ohsaka T (2010) Enhanced catalytic reduction of oxygen at tantalum deposited platinum electrode. Chem Commun 46(7):1165–1167
Masud J, Alam MT, Awaludin Z, El-Deab MS, Okajima T, Ohsaka T (2012) Electrocatalytic oxidation of methanol at tantalum oxide-modified Pt electrodes. J Power Sources 220:399–404
Korovina A, Garsany Y, Epshteyn A, Purdy AP, More K, Swider-Lyons KE, Ramaker DE (2012) Understanding oxygen reduction on tantalum oxyphosphate and tantalum oxide supported platinum by X-ray absorption spectroscopy. J Phys Chem C 116(34):18175–18183
Seo J, Cha D, Takanabe K, Kubota J, Domen K (2012) Highly-dispersed Ta-oxide catalysts prepared by electrodeposition in a non-aqueous plating bath for polymer electrolyte fuel cell cathodes. Chem Commun 48(72):9074–9076
Ishihara A, Tamura M, Matsuzawa K, Mitsushima S, Ota K (2010) Tantalum oxide-based compounds as new non-noble cathodes for polymer electrolyte fuel cell. Electrochim Acta 55(26):7581–7589
Xiao L, Huang B, Zhuang L, Lu J (2011) Optimization strategy for fuel-cell catalysts based on electronic effects. RSC Advances 1(7):1358–1363
Kukli K, Ritala M, Leskelä M (2000) Atomic layer deposition and chemical vapor deposition of tantalum oxide by successive and simultaneous pulsing of tantalum ethoxide and tantalum chloride. Chem Mat 12(7):1914–1920
Shin Y, Kim JY, Wang C, Bonnet JF, Scott Weil K (2009) Controlled deposition of covalently bonded tantalum oxide on carbon supports by solvent evaporation sol–gel process. Surf Sci 603(15):2290–2293
Li Q, Liang C, Tian Z, Zhang J, Zhang H, Cai W (2012) Core–shell Ta x O@Ta2O5 structured nanoparticles: laser ablation synthesis in liquid, structure and photocatalytic property. CrystEngComm 14(9):3236–3240
Ishihara A, Doi S, Mitsushima S, Ota K (2008) Tantalum (oxy)nitrides prepared using reactive sputtering for new nonplatinum cathodes of polymer electrolyte fuel cell. Electrochim Acta 53(16):5442–5450
Díaz B, Światowska J, Maurice V, Pisarek M, Seyeux A, Zanna S, Tervakangas S, Kolehmainen J, Marcus P (2012) Chromium and tantalum oxide nanocoatings prepared by filtered cathodic arc deposition for corrosion protection of carbon steel. Surf Coat Tech 206(19–20):3903–3910
Díaz B, Światowska J, Maurice V, Seyeux A, Härkönen E, Ritala M, Tervakangas S, Kolehmainen J, Marcus P (2013) Tantalum oxide nanocoatings prepared by atomic layer and filtered cathodic arc deposition for corrosion protection of steel: comparative surface and electrochemical analysis. Electrochim Acta 90:232–245
Suzuki TM, Nakamura T, Saeki S, Matsuoka Y, Tanaka H, Yano K, Kajino T, Morikawa T (2012) Visible light-sensitive mesoporous N-doped Ta2O5 spheres: synthesis and photocatalytic activity for hydrogen evolution and CO2 reduction. J Mater Chem 22(47):24584–24590
Macagno V, Schultze JW (1984) The growth and properties of thin oxide layers on tantalum electrodes. J Electroanal Chem 180(1–2):157–170
Wang K, Liu Z, Cruz TH, Salmeron M, Liang H (2010) In situ spectroscopic observation of activation and transformation of tantalum suboxides. J Phys Chem A 114(7):2489–2497
Sanz JM, Hofmann S (1983) Auger electron spectroscopy and X-ray photoelectron spectroscopy studies of the oxidation of polycrystalline tantalum and niobium at room temperature and low oxygen pressures. J Less Common Met 92(2):317–327
Himpsel FJ, Morar JF, McFeely FR, Pollak RA, Hollinger G (1984) Core-level shifts and oxidation states of Ta and W: Electron spectroscopy for chemical analysis applied to surfaces. Phys Rev B 30(12):7236–7241
Khanuja M, Sharma H, Mehta BR, Shivaprasad SM (2009) XPS depth-profile of the suboxide distribution at the native oxide/Ta interface. J Electron Spectrosc Relat Phenom 169(1):41–45
Lecuyer S, Quemerais A, Jezequel G (1992) Composition of natural oxide films on polycrystalline tantalum using XPS electron take-off angle experiments. Surf Inter Anal 18(4):257–261
Kerrec O, Devilliers D, Groult H, Marcus P (1998) Study of dry and electrogenerated Ta2O5 and Ta/Ta2O5/Pt structures by XPS. Mat Sci Eng B 55(1–2):134–142
Klendworth DD, Walton RA (1981) Complex halides of the transition metals. 29. Synthesis, characterization, and electrochemistry of tertiary phosphine complexes of niobium and tantalum halide clusters. Inorg Chem 20(4):1151–1155
Bursten BE, Green MR, Katovic V, Kirk JR, Lightner D (1986) Electrochemistry of niobium(IV) and tantalum(IV) complexes: ligand additivity in d1 octahedral complexes. Inorg Chem 25(6):831–834
Babushkina OB, Ekres S (2010) Spectroscopic study of the electrochemical behaviour of tantalum(V) chloride and oxochloride species in 1-butyl-1-methylpyrrolidinium chloride. Electrochim Acta 56(2):867–877
Ispas A, Adolphi B, Bund A, Endres F (2010) On the electrodeposition of tantalum from three different ionic liquids with the bis(trifluoromethyl sulfonyl) amide anion. Phys Chem Chem Phys 12(8):1793–1803
Hofmann S, Sanz JM (1982–1983) Quantitative XPS analysis of the surface layer of anodic oxides obtained during depth profiling by sputtering with 3 keV Ar+ ions. J Trace Microprobe Tech 1 (3):213–264
Masud J, Alam MT, Miah MR, Okajima T, Ohsaka T (2011) Enhanced electrooxidation of formic acid at Ta2O5-modified Pt electrode. Electrochem Commun 13(1):86–89
Mitchell DF, Sproule GI, Graham MJ (1990) Sputter reduction of oxides by ion bombardment during Auger depth profile analysis. Surf Inter Anal 15(8):487–497
Oh MH, Lee N, Kim H, Park SP, Piao Y, Lee J, Jun SW, Moon WK, Choi SH, Hyeon T (2011) Large-scale synthesis of bioinert tantalum oxide nanoparticles for X-ray computed tomography imaging and bimodal image-guided sentinel lymph node mapping. J Am Chem Soc 133(14):5508–5515
Vioux A (1997) Nonhydrolytic sol–gel routes to oxides. Chem Mat 9(11):2292–2299
Corriu R, Leclercq D, Lefevre P, Mutin PH, Vioux A (1992) Preparation of monolithic binary oxide gels by a nonhydrolytic sol–gel process. Chem Mater 4(5):961–963
Corriu RJP, Leclercq D, Lefevre P, Mutin PH, Vioux A (1992) Materials chemistry communications. Preparation of monolithic metal oxide gels by a non-hydrolytic sol–gel process. J Mater Chem 2(6):673–674
Corriu RJP, Leclercq D, Lefèvre P, Mutin PH, Vioux A (1992) Preparation of monolithic gels from silicon halides by a non-hydrolytic sol–gel process. J Non-Cryst Solids 146:301–303
Acknowledgments
The present work was financially supported by Grant-in-Aid for Scientific Research (A) (number 19206079) to T.O. from the Ministry of Education, Culture, Sport, Science and Technology (MEXT), Japan. J. G. S. M and Z. A gratefully acknowledge the Government of Japan for MEXT Scholarship.
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Moo, J.G.S., Awaludin, Z., Okajima, T. et al. An XPS depth-profile study on electrochemically deposited TaO x . J Solid State Electrochem 17, 3115–3123 (2013). https://doi.org/10.1007/s10008-013-2216-y
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DOI: https://doi.org/10.1007/s10008-013-2216-y