The Influence of the Structural and Morphological Properties of WO3 Thin Films Obtained by PLD on the Photoelectrochemical Water-Splitting Reaction Efficiency (original) (raw)
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Study of photoactivity of tungsten trioxide (WO3) for water splitting
Thin Solid Films, 2007
The paper presents the properties of WO 3 films considering the possibility to build a photoelectrochemical cell (PECC) for hydrogen production. The photocurrent response of the PECC containing WO 3 /TCO as photoanode and Pt as cathode was analysed. The morphology, crystalline structure and electrical aspects were investigated. Tungsten trioxide (WO 3 ) thin film with porous morphology and high crystallinity was obtained using the spray pyrolysis deposition technique.
Photoelectrochemical properties of WO3 thin films prepared by electrodeposition
2013
Tungsten trioxide (WO 3 ) thin films were synthesised by electrodeposition using peroxotungtic acid as the precursor electrolyte solution for use as photoanodes in a photoelectrochemical cell for solar hydrogen applications. The films were coated at deposition potentials varying from 0.30 to 0.90 V versus Ag/AgCl in order to study the effect of the potential on the mineralogical, morphological, optical, and photoelectrochemical properties of the nanoparticulate films.
ACS Catalysis, 2018
Further advancement in sunlight-driven splitting of water as a means of producing hydrogen and oxygen is mainly hampered by the availability of easy-to-prepare, inexpensive n-type semiconductor materials able to operate as stable and efficient photoanodes in a water photoelectrolysis cell. Here, we demonstrate that photocatalytic water oxidation currents on thin-layer semitransparent WO 3 electrodes, deposited by one-step sol-gel method on conductive oxide F-SnO 2 substrates, are dramatically improved following additional higher-temperature (ca 700°C) annealing. Largely reduced recombination of charge carriers photogenerated in activated WO 3 associated with enhanced light absorption yields at 1.23 V vs RHE, under simulated solar AM 1.5G irradiation (100 mW cm-2), water photo-oxidation currents close to 4.2 mA cm-2 on a 1.2 µm-thick photoanode-about 2 times larger than on the electrodes of the same thickness only annealed at 550°C. The relative enhancement of the photocurrent induced by the further annealing at 700°C scaled up with decreasing the film thickness with a threefold increase observed for the thinnest tested, 0.25 µm-thick WO 3 electrode that reaches 2.75 mA cm-2. We obtained such high photocatalytic water splitting performance without depositing any additional water oxidation catalyst.
ACS Applied Materials & Interfaces, 2013
The current work demonstrates the importance of WO 3 crystallinity in governing both photoenergy conversion efficiency and storage capacity of the flower structured WO 3 electrode. The degree of crystallinity of the WO 3 electrodes was varied by altering the calcination temperature from 200 to 600°C. For the self-photochargeability phenomenon, the prevailing flexibility of the short-range order structure at low calcination temperature of 200°C favors the intercalation of the positive cations, enabling more photoexcited electrons to be stored within WO 3 framework. This leads to a larger amount of stored charges that can be discharged in an on-demand manner under the absence of irradiation for H 2 generation. The stability of the electrodes calcined at 200°C, however, is compromised because of the structural instability caused by the abundance insertion of cations. On the other hand, films that were calcined at 400°C displayed the highest stability toward both intercalation of the cations and photoelectrochemical water splitting performance. Although crystallinty of WO 3 was furthered improved at 600°C heat treatment, the worsened contact between the WO 3 platelets and the conducting substrate as induced by the significant sintering has been more detrimental toward the charge transport.
Tuning Structural Properties of WO3 Thin Films for Photoelectrocatalytic Water Oxidation
Catalysts
The preparation of tungsten oxide (WO3) thin film by direct current (DC) reactive sputtering magnetron method and its photoelectrocatalytic properties for water oxidation reaction are investigated using ultraviolet-visible radiation. The structural, morphological, and compositional properties of WO3 are fine-tuned by controlling thin film deposition time, and post-annealing temperature and environment. The findings suggest that the band gap of WO3 can be controlled by adjusting the post-annealing temperature; the band gap decreased from 3.2 to 2.7 eV by increasing the annealing temperature from 100 to 600 °C. The theoretical calculations of the WO3 bandgap and the density of state are performed by density functional theory (DFT). Following the band gap modification, the photoelectrocatalytic activity increased and the maximum photocurrent (0.9 mA/cm2 at 0.6 VSCE) is recorded with WO3 film heated at 500 °C. The WO3 film heated under air exhibits much better performance in photoelectr...
Journal of Physics: Conference Series, 2007
The structural (Raman spectroscopy), electrical (Current-Voltage analysis) and photoelectrical (Photoconduction analysis) properties of the tungsten trioxide films annealed in air at different temperature are reported. The influence of the thermal post-treatment on the morphology of the films and the role of oxygen vacancies on the WO 3 opto-electronic properties has been discussed and linked with possible applications in hydrogen production in a PECC.
2021
TiO2 nanorod as a superior nanostructure has attracted a lot of attention to exert in the photocatalytic and photoelectrocatlytic applications in recent years. Nevertheless, its practical usage is restricted by a number of limitations such as the large band gap energy, the low rate of photo-induced carriers generation and the high rate of charge carriers recombination. Therefore in this study, incorporation of TiO2 nanorod with WO3 is proposed as a suitable approach to overcome these defects. In this regard, WO3-TiO2 nanorod was constructed by a facile one pot hydrothermal method in two incessant steps and was then employed as a potent photoanode for photoelectrocatalytic hydrogen generation. The morphology, elemental compositions and optical properties were characterized by the FESEM, EDS and DRS analysis, respectively. Furthermore, voltammetry analyses were performed to assay the photoelectrochemical features of WO3-TiO2 nanorod. The results confirmed that the incorporation of TiO...