Triple-layered nanostructured WO₃ photoanodes with enhanced photocurrent generation and superior stability for photoelectrochemical solar energy conversion

Abstract

Unique nanorods/nanoparticles/nanoflakes (NRs/NPs/NFs) WO3 triple-layers are grown on a metallic W foil by a simple one-step anodization method. The triple-layered structure is formed through a self-organization process, the film thickness (up to 3 μm) being controlled by the anodization time. A first layer made of an array of WO3 densely-packed vertically-aligned NRs (1.2-1.4 μm in height) grow atop the tungsten foil, followed by a second layer of small NPs (50-80 nm) and finally a third layer made of rectangular NFs (200-300 nm). When irradiated by white light in a photoelectrochemical cell these WO3 triple-layers generate a photocurrent as high as 0.9 mA cm(-2) at 1.2 V/RHE. Moreover, we show that the stability of the triple-layered WO3 photoanodes can be considerably enhanced by adding an ultrathin (10 nm) TiO2 protective overlayer.

Electrosprayed heterojunction WO3/BiVO4 films with nanotextured pillar structure for enhanced photoelectrochemical water splitting

“…The monoclinic phase of WO 3 is highly stable at room temperature and yields greater PEC activity than the orthorhombic phase. 33 The XRD pattern of pure BiVO 4 shows diffraction peaks corresponding to the (110) 14-0688 confirmed the monoclinic scheelite structure of BiVO 4 . The PEC activity of monoclinic BiVO 4 has been observed to be better than that of the zircon or tetragonal scheelite BiVO 4 crystal structures.…”

Photoelectrochemical water splitting using WO3 photoanodes: the substrate and temperature roles

“…18 Actually, the current values obtained are in straight agreement with the ones reported in literature. 27,33 For WO3/FTO sample, at 25 °C and under dark conditions, the current onset is observed for a potential higher than 2.1 VRHE (the electrolysis threshold for water oxidation with WO3/FTO photoanodes) -cf. Fig.…”

“…26, 27 The morphology (e.g. shape, size and porosity) and crystallinity of WO3 nanoparticles depend critically on preparation parameters and annealing temperatures, being also limiting factors for PEC cell performance.…”

Hydrothermal preparation and supercapacitive performance of flower-like WO3·H2O/reduced graphene oxide composite

“…Tungsten trioxide (WO 3 ) and its hydrates (WO 3 ·xH 2 O, x = 0∼2), as one of the important transition metal oxides, are extensively investigated due to the promising properties and a wide spectrum of applications in gas sensors [11,12], photocatalysis [13,14], electrochromic devices [15,16], electronic devices [17], dye-sensitized solar cells [18,19], adsorbent [20] and lithium ion batteries [21,22]. The capacitive behaviors of the nanostructured tungsten oxides have been also investigated as supercapacitor electrodes [23][24][25][26][27][28][29].…”