Insights into the Fabrication of Self-Ordered Titanium Dioxide Nanotube Layers and Electrodeposition of 1D Zinc Nanostructures using Deep Eutectic Solvents

Ordered array structures with uniform sized holes of nanometer dimensions are important because of demand for the development of various kinds of functional nanodevices.

Several electrolytes for preparation of anodic titania with porous nanotubular (TNT) structure  have been proposed, such as the water-based ones with different additives and the organic electrolytes. While titania nanotubes produced from water-based electrolytes had sidewall inhomogeneity (ripples) and low aspect ratio, anodizing in organic electrolyte systems such as ethylene glycol 1, 2 resulted in the formation of high-ordered and long (more than 250 µm) tubes with smooth walls.

In the last two decades, room temperature ionic liquids have been in the limelight of scientists and engineers in diverse areas. The possibility of TNT synthesis from ionic liquids was also demonstrated and It was shown that the ionic liquids´ structure and their composition as well as the anodization potential can govern the morphology and the properties of TiO2 nanotubes.

Deep eutectic solvents (DES) based on choline chloride are the most widespread quasi-ionic liquids. Besides common ionic liquids properties, DES are also cheap, nontoxic and mainly biodegradable 3, 4. Deep eutectic solvents of this type contain choline chloride and various hydrogen bond donors (HBD). The wide range of HBD allows the tuning of DES properties.

In the present study, beyond the use of ethylene glycol-based electrolyte in the presence of fluoride ions we explored the fabrication of TNT by electrochemical anodization of titanium in choline chloride based deep eutectic solvents with various hydrogen bond donors, such as ethylene glycol, urea and malonic acid. The influence of different synthesis parameters (fluoride content, temperature, voltage) on the morphology and geometry of the resultant TiO2 nanotubular layers was demonstrated. Moreover, basic physicochemical properties such as crystalline structure and photoelectrochemical properties of the obtained films were investigated in the work 5.

Zinc electrochemical deposition in porous anodic titania from 0.5 M ZnCl2 solution in choline chloride based deep eutectic solvent is reported in order to the formation of nanorods and nanowires 6. Electroreduction is performed by a pulsed technique in titanium dioxide templates modified in three different ways. Titania nanotubes were formed in ethylene glycol-based electrolyte with 0,38% (wt) ammonium fluoride and 1,79% (wt) of water. The templates have been used as-prepared and with modification in order to obtain a homogeneous pore filling and a high fill-factor.

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  4. D. M. F. Endres, A. Abbott, Electrodeposition from Ionic Liquids, WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim (2008.).
  5. M. Starykevich, H. Maltanava, J. Tedim, S. K. Poznyak, and M. G. S. Ferreira, J. Electrochem. Soc., 166(10): H377-H386 (2019).
  6. M. Starykevich, A. N. Salak, M. Zheludkevich, and M. G. S. Ferreira, J. Electrochem. Soc., 164 (6) D335-D341 (2017).

Acknowledgments are due to M. Starykevich (University of Aveiro), for developing the experimental work.

Mário G. S. Ferreira

Mário Ferreira has made contributions in a number of areas related to corrosion and protection, such as electronic structure of passive films, corrosion of galvanized steel, aluminum, magnesium alloys and reinforced concrete, paints, anodizing, biomaterials, atmospheric corrosion, hybrid sol-gel films, inhibitors, self-healing and nanostructured coatings, localized electrochemical techniques.

He is Full Professor at University of Aveiro, Portugal. He is a member of the Associate Laboratory, Aveiro Institute of Materials (CICECO), University of Aveiro. He was Head of the Department of Materials and Ceramic Engineering of the University of Aveiro, 2011-2017. He is the coordinator of the Surface Engineering and Corrosion Protection Group at CICECO/University of Aveiro.

Mário Ferreira has been active in the field of corrosion for 40 years and has made major contributions in corrosion through teaching and research.

Mário Ferreira’s publications are in top journals that publish on corrosion. The Scopus database reports, 354 cited publications, an h-index=80 (Jan 2021), which is extremely high for corrosion area and reflects the impact of his work. He edited 4 scientific books, is co-author of 18 book chapters and 5 patents. He was the leader (of the whole project or the Portuguese participation) of several (dozen) projects of Research & Development. Under the EU he received funds from several programmes, such as: BRITE- EURAM, ECSC, Science, COMETT, Framework Programmes. During his career, he has trained a considerable number of M.Sc. and Ph.D. students and post-docs, many of whom are now making major contributions on their own. He has been frequently invited for keynote and plenary talks.

In many of his works apart from fundamental research he participated in many industrial oriented projects with large companies, as EADS (Germany), FIAT (Italy), ThyssenKrupp (Germany), Voestalpine (Austria), SIKA (Switzerland), TataSteels (Netherlands), CIN (Portugal), Chemetall (Germany), etc, involving international cooperation between industry and academy. He participated also in several collaborative projects involving different countries in European Union, South America, East Europe, Japan.

He was a Member of the Executive Committee “F-2 Corrosion” (1994-1997) and Executive Committee of “F-7 Surface Characterization” (1994-2003) of the ESCS Technical Research Programme of Steel of European Union and Member of the Executive Committee of SERDEC of the same Programme.

From 1993 to 2008 he belonged to the Executive Board of ICEMS – Institute of Materials and Surface Science and Engineering, Instituto Superior Técnico, Lisbon. In the same period, he was Leader of the Corrosion and Environmental Effects research group.

Mário Ferreira was co-founder of SmallMaTec LDA (innovation-driven company that offers integrated solutions for protection of metal structures against corrosion and biofouling failure), which was a spin-off of university of Aveiro (since 2010).

He organised in Portugal different international corrosion events, such as, Electrochemical Methods for Corrosion Research (EMCR 1994), EUROCORR 2005, NATO School in Electrochemical Methods in Corrosion, ASST 2015, among others.

He has been extremely active in scientific societies, representing Portugal in the International Corrosion Council, participating in different working parties of the European Federation of Corrosion, and for two years a member of its Board of Administrators. He was also Member of the “Steel Advisory Group” of the “Research Steel and Coal Fund” of European Union for 10 years, up to 2019. He was Deputy Director-General for Higher Education (Ministry of Science and Higher Education of Portugal) (2003-2007) and Member of the Scientific Council for Exact Sciences and Engineering of “The Foundation for Science and Technology” (FCT), Portugal (2013-2016).

Mário Ferreira received the “H.H. Uhlig Award” of Corrosion Division of The Electrochemical Society (2013), CAVALLARO Gold Medal, Univ. Ferrara / EFC (2014), Fellow of the International Society of Electrochemistry (ISE), Fellow of The Electrochemical Society (ECS), European Corrosion Medal of the European Federation of Corrosion/EFC (2017), Engineers Association Award – Senior Adviser Member (2015).