Customized WO3 nanoplatelets as visible-light photoelectrocatalyst for the degradation of a recalcitrant model organic compound (methyl orange)

Abstract

WO3 nanoplatelets have been synthesized by electrochemical anodization in acidic electrolytes containing two different complexing agents: fluorides and hydrogen peroxide. The influence of the morphology and size of these nanoplatelets on their photoelectrocatalytic performance has been studied following the degradation of a model organic recalcitrant compound, such as methyl orange (MO). The effect of several supporting electrolytes on this photodegradation process has also been checked.The best MO decoloration was observed for nanoplatelets fabricated in the presence of low H2O2 concentrations, whose distribution and small size made them expose a very high surface area to the problem solution. With this nanostructure, decoloration efficiencies of ca. 100% were obtained after just 60 min. This result is considerably better than others reported in similar works, indicating the excellent behavior of these WO3 nanoplatelets as photoelectrocatalysts.

Tungsten oxide-based visible light-driven photocatalysts: crystal and electronic structures and strategies for photocatalytic efficiency enhancement

“…11. These morphologies can be classified into zerodimensional (0D, e.g., spherical and pseudo-spherical NPs 102,[126][127][128] ), one-dimensional (1D, e.g., nanorods, 120 nanowires, 114 nanobelts, 129 nanofibers 130,131 and nanotubes 23 ), two-dimensional (2D, e.g., nanoplatelets, 132 nanoplates 48 and nanosheets 133 ) and three-dimensional (3D, e.g., porous interconnected structures, 134,135 core-shell structures [136][137][138][139] and hierarchical structures assembled by low-dimensional building blocks 46,51,[140][141][142][143][144] ) according to the dimensionality. A schematic illustration of simplified structures in different dimensionalities is demonstrated in Fig.…”

“…The doped metal ions on the surface of WO X could trap and localize electrons around them and enhance the photo-induced electron density on the active sites, so as to improve the electron-giving ability Fig. 11 Typical morphologies of WO X photocatalysts from the literature: QDs (a), 126 monodisperse nanoparticles (b), 128 aggregated nanoparticles (c), 42 nanorods (d), 77 nanowires (e), 98 nanofibers (f ), 131 nanosheets (g), 133 nanosheets (h), 50 nanoplates (i), 48 hollow microspheres ( j), 137 multipleshell hollow spheres (k), 139 sphere-in-shell microstructures (l), 138 hierarchical structures (m), 141 flower-like microstructures (n), 142 flower-like microstructures (o), 143 cylindrical-stack microstructures ( p), 143 hierarchical structures (q), 144 and 3D ordered macroporous structures (r). 135 Reproduced with permission from ref.…”

Photoelectrocatalyzed degradation of a pesticides mixture solution (chlorfenvinphos and bromacil) by WO3 nanosheets

“…In addition, WO3 has good stability in acidic environments [36]. However, in spite of all its good properties, nanostructured WO3 photoanodes have been barely used to degrade persistent organic pollutants, especially if compared with other semiconducting oxides such as TiO2 [37,[39][40][41][42][43][44][45][46].…”

Visible-light photoelectrodegradation of diuron on WO3 nanostructures

“…PEC performance of the WO3 nanostructures was evaluated by degrading a 20 mg L -1 diuron solution with 0.1 M H2SO4 as a supporting electrolyte, under 420 nm light (by using a 1000 W Xe light source, 100 mW cm -2 at 420 nm) and applying an external potential of 1 V. The acidic supporting electrolyte was used to enhance the photoelectrocatalytic performance of nanostructures, according to a previous work [21].…”

“…Among the semiconductor oxides investigated for PEC applications, WO3 nanostructures present interesting properties, such as band gap values around 2.6 eV (λ = 477 nm) that permit the absorption of visible light and high chemical and photoelectrochemical resistance in acidic environments [1,10]. WO3 photoanodes have been synthesized to degrade organic compounds such us dyes [11][12][13][14][15][16][17][18][19][20][21], pesticides [22] or drugs and other chemicals [23][24][25][26][27]. This work studies the PEC degradation of diuron (Figure 2), a persistent herbicide, by using high-performance WO3 nanostructures.…”