| Title |
Composites based on electrodeposited WO3 and TiO2 nanoparticles for photoelectrochemical water splitting / |
| Authors |
Levinas, Ramūnas ; Podlaha, Elizabeth ; Tsyntsaru, Natalia ; Cesiulis, Henrikas |
| DOI |
10.3390/ma17194914 |
| Full Text |
|
| Is Part of |
Materials.. Basel : MDPI AG. 2024, vol. 17, iss. 19, art. no. 4914, p. 1-15.. eISSN 1996-1944 |
| Keywords [eng] |
electrodeposition ; IMPS of OER ; photoelectrochemical water splitting ; tungsten trioxide titania composite |
| Abstract [eng] |
Photoelectrochemically active WO3 films were fabricated by electrodeposition from an acidic (pH 2), hydrogen-peroxide-containing electrolyte at −0.5 V vs. SCE. WO3-TiO2 composites were then synthesized under the same conditions, but with 0.2 g/L of anatase TiO2 nanoparticles (⌀ 36 nm), mechanically suspended in the solution by stirring. After synthesis, the films were annealed at 400 °C. Structural characterization by XRD showed that the WO3 films exhibit the crystalline structure of a non-stoichiometric hydrate, whereas, in WO3-TiO2, the WO3 phase was monoclinic. The oxidation of tungsten, as revealed by XPS, was W6+ for both materials. Ti was found to exist mainly as Ti4+ in the composite, with a weak Ti3+ signal. The efficiency of the WO3 films and composites as an oxygen evolution reaction (OER) photo-electrocatalyst was examined. The composite would generate approximately three times larger steady-state photocurrents at 1.2 V vs. SCE in a neutral 0.5 M Na2SO4 electrolyte compared to WO3 alone. The surface recombination of photogenerated electron–hole pairs was characterized by intensity-modulated photocurrent spectroscopy (IMPS). Photogenerated charge transfer efficiencies were calculated from the spectra, and at 1.2 V vs. SCE, were 86.6% for WO3 and 62% for WO3-TiO2. Therefore, the composite films suffered from relatively more surface recombination but generated larger photocurrents, which resulted in overall improved photoactivity. |
| Published |
Basel : MDPI AG |
| Type |
Journal article |
| Language |
English |
| Publication date |
2024 |
| CC license |
|
