2022-Sustainable Industrial Processing Summit
SIPS2022 Volume 4 Kipouros Intl. Symp. Molten Salt, Ionic & Glass-forming Liquids & Powdered Materials
| Editors: | F. Kongoli, R. Fehrmann, V. Papangelakis, I.Paspaliaris, G. Saevarsdottir. |
| Publisher: | Flogen Star OUTREACH |
| Publication Year: | 2022 |
| Pages: | 100 pages |
| ISBN: | 978-1-989820-40-7(CD) |
| ISSN: | 2291-1227 (Metals and Materials Processing in a Clean Environment Series) |
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Nanoscale Tungsten Carbides Prepared by Electrochemical Synthesis in Molten Salts
Sergei Kuleshov1;1INSTITUTE OF GENERAL AND INORGANIC CHEMISTRY, Kiev, Ukraine;
Type of Paper: Regular
Id Paper: 76
Topic: 13
Abstract:
In recent years, tungsten carbides are extensively used in engineering applications, such as cutting and mining tools, surface coatings, chemical and electronic industries [1]. Also, tungsten carbides (especially nanoscale) are widely used as a catalytic material [2, 3]. Most modern methods of producing tungsten carbides are hindered by either multi-stage processes or their high energy costs. One of the most attractive methods for producing nanoscale materials is by means high-temperature electrochemical synthesis (HTES). The essence of the method of HTES is the use of electrochemical processes for the decomposition of the carbon and tungsten precursor with further interaction of reduction products and the formation of carbides. This paper is devoted to the production of nanoscale tungsten carbides by the method of HTES. Taking into account specific features of partial and joint electrochemical reduction of carbon and tungsten in different systems, we chose optimum conditions for obtaining highly dispersed tungsten carbides. A high yield of nanopowders of hexagonal α-WC with nano-dimensional carbon structures could be obtained using the NaCl–KCl–Li2CO3 (2*10-3 mol/cm3)–Na2W2O7 (6*10-4 mol/cm3) molten salt system with pressure of CO2 10 atm. at 750 °C. The current density is 0.2 A/cm2. The particles were characterized using XRD, SEM, TEM, Raman spectroscopy, BET and DTG methods. The size of WC and W2C can be less than 8 nm with the specific surface area of the powders 25–30 m2/g. Based on SEM images, it has been found that the WC nanoparticles are connected together into conglomerates, which are enveloped in a “fur coat” and which apparently consist of carbon. Four types of particles have been established: curdled, slightly coherent conglomerates, layered particles individual nanofibers and nanorods. These properties allow the use of electrolytic tungsten carbides as a electrocatalyst. The electrocatalytic properties of the synthesis carbides for the hydrogen evolution reaction (HER) in acid solution were investigated by using the electrochemical techniques of cyclic voltammetry. Investigations have shown that it is possible to produce by the HTES nanosized powders of tungsten carbides which can be used as electrode material for the HER in the solution of H2SO4.
Keywords:
Carbon; Electrodeposition; Electrolysis; Moltensalt; Nanomaterials; Refractory; Tungsten;References:
[1] A. S. Kurlov, A. I. Gusev, Tungsten Carbides, Springer Ser. Mater. Sci, 2013. [2] S. Emin, C. Altinkaya, A. Semerci, H. Okuyucu, A. Yildiz, P. Stefanov, Appl. Catal., B. 236 (2018) 147-153 [3] Y. Wang, L. Zhang, X. Meng, L. Feng, T. Wang, W. Zhang, N. Yang, Electrochim. Acta. 319 (2019) 775-782