Abstract

MORALES GOMERO, Juan C; CORZO LUCIONI, Alberto; ALARCON CAVERO, Hugo  and  LAZO HOYOS, Darío. Synthesis and Characterization of (WO3)n Via Sol-Gel Films Using Dip Coating Technique. Rev. Soc. Quím. Perú [online]. 2017, vol.83, n.4, pp.420-436. ISSN 1810-634X.

In the present investigation (WO3)n films were synthesized by Sol-Gel methodology by dip coating techniques using Na2WO4 as precursor salt to form polytungstic acid ((WO3)n.nH2O), which by dehydration formed the oxide (WO3)n that was deposited in two different substrates: 316L stainless steel and FTO (Fluorine doped Tin Oxide), which were deposited under the same experimental conditions and subsequently sintered at 400 ° C for a lapse of 30 minutes in both cases. It was observed that the film of (WO3)n deposited on steel presented a greater photocurrent generated of 133 μAcm-2, compared to 29 μAcm-2 for (WO3)n film measured by cyclic voltammetry in a potentiostat (AUTOLAB PGSTAT302N) against the FTO-supported film. The films were characterized using Fourier Transform Infrared Spectroscopy (FTIR) techniques, using the SHIMADZU IR PRESTIGE 21 FTIR spectrophotometer to recognize W-O-W (826 cm-1) links on the surface of the FTO and W-O-W links (652 cm-1), W=O (953 cm-1), W-O (1414 cm-1) and O-H vibration (2338 cm-1) on the steel surface; Raman spectroscopy at 532 nm to confirm symmetric stretches of W-O bonds that could not be clearly identified by FTIR; X-ray diffraction (XRD) to confirm the crystalline structure of the films, finding a predominantly monoclinic structure whose base structure corresponds to WO3, and an approximate estimate of crystallite size of 27,4 nm determined by the equation of Debye Scherrer and X-ray Dispersive Energy (EDX) for elemental analysis, yielding a centesimal composition of 77,7 % by mass of W corresponding to the empirical formula of WO3, and finally a morphological analysis by Scanning Electron Microscopy (SEM) that showed which showed the formation of layers (films) with nanostructures with non-uniform particle size ranging between 50 and 100 nm

Keywords : Politungstic acid; (WO3)n; FTO; sol - gel; cyclic voltammetry.

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