The Influence of the Structural and Morphological Properties of WO3 Thin Films Obtained by PLD on the Photoelectrochemical Water-Splitting Reaction Efficiency

Abstract

Due to its physical and chemical properties, the n-type tungsten oxide (WO3) semiconductor is a suitable photoanode for water decomposition reaction. The responses of the photoelectrochemical PEC water-splitting properties as an effect of structural and optical changes of WO3 thin films, as well as the nature of electrolyte solutions, were studied in this work. The WO3 thins films have been obtained by pulsed laser deposition (PLD) on silicon (Si(001)) covered with platinum substrates using three different laser wavelengths. As the XRD (X-ray diffraction) and XTEM (cross-section transmission electron microscopy) analysis shows, the formation of highly crystalline monocline WO3 phase is formed for the film deposited at 1064 nm wavelength and poor crystalline phases with a large ordering anisotropy, characteristic of 2D structures for the films deposited at 355 nm and 193 nm wavelengths, respectively. The photogenerated current densities Jph depend on the laser wavelength, in both alkaline and acidic electrolyte. The maximum values of the photocurrent density have been obtained for the sample prepared with laser emitting at 355 nm. This behavior can be correlated with the coherent crystallized atomic ordering that appear for long distances (10–15 nm) in the (001) plane of the monoclinic WO3 phase structure films obtained at 355 nm laser wavelength. All the samples show poor current density in dark conditions and they are very stable in both acidic and alkaline solutions. The highest photocurrent density value is obtained in acidic solution for the WO3 thin film prepared by 355 nm laser (29 mA/cm2 at 1.6 V vs. RHE (1.35 V vs. Ag/AgCl)).

High-Voltage Etching-Induced Terrace-like WO3 Photoanode for Efficient Photoelectrochemical Water Splitting

“…Photoelectrochemical (PEC) water splitting, which utilizes solar energy to produce hydrogen, has emerged as a promising technology for renewable hydrogen production. , A PEC system benefits charge separation and allows oxidation and reduction reaction products to be collected separately. Since the sluggish oxygen evolution reaction (OER) that occurs at the photoanode is the rate-determining step for the overall PEC redox reaction, developing efficient photoanodes is crucial for achieving exceptional PEC activities . However, it is hard to find one single material that exhibits supreme light harvesting ability, appropriate optical band gap, high chemical and thermostability, and good catalytic performance.…”

“…The morphology engineering to control the geometry of WO 3 at the nanoscale makes WO 3 ideal for facilitating charge transfer and redox reactions at the surface of the photoanode . The developments of WO 3 photoanodes with various surface morphologies, including nanoparticles, nanoporous structures, nanotubes, nanoplates, and three-dimensional branched nanostructures, have been reported using several fabrication techniques, including hydrothermal, anodization, thermal evaporation, and sol–gel. ,− Among these approaches, anodization is simple, economical, and able to produce large-scale porous nanostructured WO 3 . The morphology and geometrical features of WO 3 can be controlled by the careful adjustment of anodization parameters, such as anodization voltage, electrolyte composition, temperature, and duration .…”

“…Since the sluggish oxygen evolution reaction (OER) that occurs at the photoanode is the ratedetermining step for the overall PEC redox reaction, developing efficient photoanodes is crucial for achieving exceptional PEC activities. 3 However, it is hard to find one single material that exhibits supreme light harvesting ability, appropriate optical band gap, high chemical and thermostability, and good catalytic performance. An n-type semi- conductor material, tungsten trioxide (WO 3 ), has emerged as one of the highly promising candidates for photoanode material due to its intrinsic properties.…”

Temperature-mediated Phase Transformation and Optical Properties of Tungsten Oxide Nanostructures Prepared by Facile Hydrothermal Method

“…Recent developments in designing and controlling WO 3 nanostructure preparation have made these potentials more appealing for researchers and engineers [1][2][3][4][5][6][7][8][9][10]. Up to now, tungsten oxide has been prepared by various methods, which can be named as sol-gel [11], physical vapor ©2022 Vietnam Academy of Science and Technology deposition [12], pulsed laser deposition [13], solvothermal [14], hydrothermal [9,15], or electrospinning [16]. .…”

Au nanoclusters-decorated WO3 nanorods for ultrasensitive photoelectrochemical sensing of Hg2+

“…[14][15][16][17][18][19] As an important n-type inorganic semiconductor, WO 3 has been extensively used in photocatalysis, electrochromic devices, gas sensing, and biosensing because of its characteristics of simple synthesis, high stability and low cost. [20][21][22][23] Recently, WO 3 has been widely used in PEC sensing because of its inherent visible light absorbance. [24][25][26][27][28] However, the low photoelectric conversion efficiency of WO 3 alone still limits the sensitivity of PEC sensors because of the fast electron-hole recombination.…”