Direct Electrochemical Reduction of Solid TiO₂ in [BMIM]BF₄-CaCl₂ Ionic Liquid

Abstract:

The direct electrochemical reduction of solid titanium dioxide (TiO₂) is conducted in [BMIM]BF₄-CaCl₂ ionic liquid (IL) at 100 °C using sintered TiO₂ as cathode and graphite rod as anode at an electrolysis potential of 3.2 V. Cyclic voltammetry is used to investigate the mechanism and feasibility of the direct electrochemical reduction of solid TiO₂ in [BMIM]BF₄-CaCl₂ IL at 100 °C. The surface morphologies of the cathode are examined by scanning electron microscopy（SEM）. The crystal phase structure of the cathode is examined using a D8 Advance X-ray diffractometer(XRD). The results indicate that the direct electrochemical reduction of solid TiO₂ in [BMIM]BF₄-CaCl₂ IL is feasible. A significant increase in conductivity is obtained by doping graphite into the cathode, thereby enhancing deoxidation. TiO₂ reduction is conducted step by step, from outside to inside, and from high to low valence variation.

• Periodical: Applied Mechanics and Materials (Volume 492)
• Pages: 248-252
• DOI: https://doi.org/10.4028/www.scientific.net/AMM.492.248
• Online since: January 2014
• Authors: Jie Chen Mu, Xu Dong Zhang, Li Peng Zhang
• Keywords: Electrochemical Reduction, Ionic Liquid (IL), TiO₂

References

[1] W. Mo, G. Deng, F. Luo, Titanium metallurgy, in, Beijing: Metallurgical Industry Press, 1998, pp.281-332.

[2] H. Li, S.M. Oppenheimer, S.I. Stupp, D.C. Dunand, L.C. Brinson, Effects of pore morphology and bone ingrowth on mechanical properties of microporous titanium as an orthopaedic implant material, Materials Transactions, 45 (2004) 1124-1131.

DOI: 10.2320/matertrans.45.1124

[3] X. NIE, L. DONG, C. BAI, D. CHEN, G. QIU, Preparation of Ti by direct electrochemical reduction of solid TiO2 and its reaction mechanism, Transactions of Nonferrous Metals Society of China, 16 (2006) s723-s727.

DOI: 10.1016/s1003-6326(06)60288-4

[4] G.Z. Chen, D.J. Fray, T.W. Farthing, Direct electrochemical reduction of titanium dioxide to titanium in molten calcium chloride, Nature, 407 (2000) 361-364.

DOI: 10.1038/35030069

[5] R.O. Suzuki, Calciothermic reduction of TiO2 and in situ electrolysis of CaO in the molten CaCl2, JPCS, 66 (2005) 461-465.

DOI: 10.1016/j.jpcs.2004.06.041

[6] I. Park, T. Abiko, T.H. Okabe, Production of titanium powder directly from TiO2 in CaCl2 through an electronically mediated reaction (EMR), JPCS, 66 (2005) 410-413.

DOI: 10.1016/j.jpcs.2004.06.052

[7] F. Endres, Ionic liquids: solvents for the electrodeposition of metals and semiconductors, ChemPhysChem, 3 (2002) 144-154.

DOI: 10.1002/1439-7641(20020215)3:2<144::aid-cphc144>3.0.co;2-#

[8] M. Ueda, H. Kigawa, T. Ohtsuka, Co-deposition of Al-Cr-Ni alloys using constant potential and potential pulse techniques in AlCl3-NaCl-KCl molten salt, Electrochim Acta, 52 (2007) 2515-2519.

DOI: 10.1016/j.electacta.2006.09.001

[9] M. Jafarian, M.G. Mahjani, F. Gobal, I. Danaee, Effect of potential on the early stage of nucleation and growth during aluminum electrocrystallization from molten salt (AlCl3-NaCl-KCl), J Electroanal Chem, 588 (2006) 190-196.

DOI: 10.1016/j.jelechem.2005.12.028

[10] T. Jiang, M.J. Chollier Brym, G. Dubé, A. Lasia, G.M. Brisard, Electrodeposition of aluminium from ionic liquids: Part II-studies on the electrodeposition of aluminum from aluminum chloride (AICl3)-trimethylphenylammonium chloride (TMPAC) ionic liquids, Surf Coat Technol, 201 (2006).

DOI: 10.1016/j.surfcoat.2005.12.024

[11] T. Jiang, M.J. Chollier Brym, G. Dubé, A. Lasia, G.M. Brisard, Electrodeposition of aluminium from ionic liquids: Part I-electrodeposition and surface morphology of aluminium from aluminium chloride (AlCl3)-1-ethyl-3-methylimidazolium chloride ([EMIm]Cl) ionic liquids, Surf Coat Technol, 201 (2006).

DOI: 10.1016/j.surfcoat.2005.10.046

[12] G. Yue, S. Zhang, Y. Zhu, X. Lu, S. Li, Z. Li, A promising method for electrodeposition of aluminium on stainless steel in ionic liquid, AlChE J, 55 (2009) 783-796.

DOI: 10.1002/aic.11698

[13] J.Z. Yang, Y. Jin, Y.H. Cao, L.X. Sun, Z.C. Tan, Studies on Electrochemical Stability of Room Temperature Ionic Liquids, CHEMICAL JOURNAL OF CHINESE UNIVERSITIES-CHINESE EDITION-, 25 (2004) 1733-1735.

[14] G.Z. Chen, D.J. Fray, Voltammetric studies of the oxygen-titanium binary system in molten calcium chloride, JElS, 149 (2002) E455.

DOI: 10.1149/1.1513985

[15] D.J. Fray, Emerging molten salt technologies for metals production, JOM Journal of the Minerals, Metals and Materials Society, 53 (2001) 27-31.

DOI: 10.1007/s11837-001-0052-5

[16] M. Ma, D. Wang, W. Wang, X. Hu, X. Jin, G.Z. Chen, Extraction of titanium from different titania precursors by the FFC Cambridge process, JAllC, 420 (2006) 37-45.

DOI: 10.1016/j.jallcom.2005.10.048

[17] G.Z. Chen, E. Gordo, D.J. Fray, Direct electrolytic preparation of chromium powder, Metallurgical and Materials Transactions B, 35 (2004) 223-233.

DOI: 10.1007/s11663-004-0024-6

[18] C. Tiyapiboonchaiya, D.R. MacFarlane, J. Sun, M. Forsyth, Polymer - in - ionic - liquid electrolytes, MmCP, 203 (2002) 1906-(1911).

[19] S. Wang, Y. Li, Reaction mechanism of direct electro-reduction of titanium dioxide in molten calcium chloride, J. Electroanal. Chem., 571 (2004) 37-42.

DOI: 10.1016/j.jelechem.2004.04.010