Enhanced Photocatalytic Activity of Hierarchical Bi2WO6 Microballs by Modification with Noble Metals

Abstract

Visible-responsive photocatalysts for environmental purification and fuel generation are, currently, highly sought after. Among the possible candidates, Bi2WO6 (BWO) has been considered due to its efficient light harvesting, stability, and promising activities. Here, hierarchical BWO microballs have been prepared using a hydrothermal method, and additionally modified with deposits of noble metals (gold, silver, copper, palladium and platinum) by the photodeposition method. The structure, morphology, photoabsorption properties, and surface composition of bare and metal-modified BWO samples were investigated by XRD, SEM, DRS and XPS analyses. The photocatalytic activity was evaluated by the oxidative degradation of model dye (methyl orange (MO)) under UV/vis, and hydrogen generation under vis and/or UV irradiation. It was found that hierarchical morphology is detrimental for high photocatalytic activity in both tested systems, resulting in the improved degradation of MO (ca. 65% during 90 min of UV/vis irradiation), and hydrogen evolution (0.1 and 0.4 μmol h−1 under vis and UV/vis irradiation, respectively). Moreover, the type of noble metal and its properties influence the overall photocatalytic performance. It was found that, under UV/vis irradiation, only platinum accelerates hydrogen evolution, whereas under vis irradiation the activity follows the order: BWO < BWO/Cu < BWO/Ag < BWO/Pt < BWO/Pd < BWO/Au. It was concluded that zero-valent metal is recommended for high vis response, probably due to plasmonic photocatalysis, efficient light harvesting ability, and co-catalytic role.

Plasmon-Enhanced Photocatalysis Based on Plasmonic Nanoparticles for Energy and Environmental Solutions: A Review

“…In another study, hydrothermal-synthesized Bi 2 WO 6 (BWO) microballs decorated by different noble metals containing gold, silver, copper, palladium, and platinum via a photodeposition method were produced to investigate the role of different noble metals in hydrogen evolution. 110 While the absorption peak of BWO was located at 450 nm, as a result of the plasmonic effect of noble metals, Au/BWO and Ag/BWO showed 545 and 490 nm absorption peaks, respectively. The hierarchical morphology resulted in the enhancement of MO degradation (about 65%) under UV−vis irradiation and higher H 2 generation (0.1 μmol h −1 under visible light and 0.4 μmol h −1 under UV−vis illumination).…”

“…In another study, hydrothermal-synthesized Bi 2 WO 6 (BWO) microballs decorated by different noble metals containing gold, silver, copper, palladium, and platinum via a photodeposition method were produced to investigate the role of different noble metals in hydrogen evolution . While the absorption peak of BWO was located at 450 nm, as a result of the plasmonic effect of noble metals, Au/BWO and Ag/BWO showed 545 and 490 nm absorption peaks, respectively.…”

Insight into the LED-assisted deposition of platinum nanoparticles on the titania surface: understanding the effect of LEDs

“…However, only by using the maximum power of the LEDs (10 W), a further extension of the absorption spectrum was noted-for the 365 nm series to 450 nm, while for the 395 nm series to 430 nm. The change in absorption spectra for analyzed samples is associated with the presence of Localized Surface Plasmon Resonance (LSPR) peaks for Pt 40 . Platinum surface plasmon resonance was observed at the wavelength of about 410-420 nm.…”

Bismuth Tungstate Nanoplates—Vis Responsive Photocatalyst for Water Oxidation

“…However, its further applications are extremely restricted because of its inherent limitations, such as poor capability to absorb visible light and speedy recombination of charge carriers. To remove these drawbacks, various BWO modification strategies have already been proposed, such as the elemental doping [14][15][16][17][18][19][20][21], surface modification (e.g., with noble metals [19,[22][23][24][25] and carbon-based materials [26][27][28][29][30][31][32]), the structural optimization [23,27,[33][34][35][36][37][38][39][40], and the construction of heterojunctions with other materials, such as Bi 2 WO 6 /TiO 2 [41], Bi 2 WO 6 /g-C 3 N 4 [42], Bi 2 WO 6 /MoS 2 [43], Bi 2 WO 6 /FeS 2 [44], Bi 2 WO 6 /CoIn 2 S 4 [45], Bi 2 WO 6 /AgIO 3 [46], Bi 2 WO 6 /CNT/TiO 2 [47], Bi 2 WO 6 /g-C 3 N 4 /TiO 2 [48], and Bi 2 WO 6 /BiOI/g-C 3 N 4 [49].…”