Enhanced Photocatalytic Activity and Stability of Bi2WO6 – TiO2-N Nanocomposites in the Oxidation of Volatile Pollutants

Abstract

The development of active and stable photocatalysts for the degradation of volatile organic compounds under visible light is important for efficient light utilization and environmental protection. Titanium dioxide doped with nitrogen is known to have a high activity but it exhibits a relatively low stability due to a gradual degradation of nitrogen species under highly powerful radiation. In this paper, we show that the combination of N-doped TiO2 with bismuth tungstate prevents its degradation during the photocatalytic process and results in a very stable composite photocatalyst. The synthesis of Bi2WO6–TiO2-N composites is preformed through the hydrothermal treatment of an aqueous medium containing nanocrystalline N-doped TiO2, as well as bismuth (III) nitrate and sodium tungstate followed by drying in air. The effect of the molar ratio between the components on their characteristics and photocatalytic activity is discussed. In addition to an enhanced stability, the composite photocatalysts with a low content of Bi2WO6 also exhibit an enhanced activity that is substantially higher than the activity of individual TiO2-N and Bi2WO6 materials. Thus, the Bi2WO6–TiO2-N composite has the potential as an active and stable photocatalyst for efficient purification of air.

Visible-Light-Active N-Doped TiO2 Photocatalysts: Synthesis from TiOSO4, Characterization, and Enhancement of Stability Via Surface Modification

“…Recently, we have shown [ 79 ] that the combination of TiO 2 -N with a Bi 2 WO 6 semiconductor can provide a nanocomposite photocatalyst, which maintains a high level of activity even under high power radiation. Herein, we show another example of the modification of TiO 2 -N to enhance its stability under long-term exposure to power radiation.…”

Kinetic Aspects of Benzene Degradation over TiO2-N and Composite Fe/Bi2WO6/TiO2-N Photocatalysts under Irradiation with Visible Light

“…The realization of heterojunction in Bi 2 WO 6 /TiO 2 -N leads to a substantial increase in the visible-light activity of this composite compared to initial TiO 2 -N [ 31 ]. For instance, the steady-state rate of CO 2 formation during the oxidation of acetone vapor under blue light (450 nm, 160 mW cm −2 ) was 0.7 and 1.0 µmol min −1 for TiO 2 -N and Bi 2 WO 6 /TiO 2 -N, respectively.…”

“…Parameters of synthesis were selected based on the results of our previous study [ 32 ] to prepare TiO 2 -N with a high activity under visible light. Bi 2 WO 6 /TiO 2 -N composite was synthesized by hydrothermal method using Bi(NO 3 ) 3 and Na 2 WO 4 precursors according to our previously published technique [ 31 ]. A molar ratio between Bi 2 WO 6 and TiO 2 -N components (5:100) was adjusted by the initial amounts of precursors and TiO 2 -N in suspension.…”

“…Many composite photocatalysts based on TiO 2 -N have been described in the literature [ 26 , 27 , 28 , 29 , 30 ]. We have previously shown that Bi 2 WO 6 /TiO 2 -N heterostructure prepared by hydrothermal method exhibits a high activity in the degradation of gaseous organic pollutants under visible light and has a high stability under power radiation for a long time [ 31 ]. Similar to TiO 2 -N, the visible-light activity of the Bi 2 WO 6 /TiO 2 -N composite can be substantially increased by depositing metal species (e.g., Fe) on its surface [ 32 ].…”

Highly Dispersion Cu2O QDs Decorated Bi2WO6 S-Scheme Heterojunction for Enhanced Photocatalytic Water Oxidation

“…These unique properties reveal that Bi 2 WO 6 can be utilized as a visible-light-driven photocatalyst for organic synthesis, CO 2 reduction, Nanomaterials 2022, 12, 2455 2 of 16 and environmental remediation [10][11][12]. Nevertheless, similar to many semiconductors, the poor utilization efficiency of solar energy and high recombination rate of pure Bi 2 WO 6 give rise to depressed photocatalytic activity and thereby cannot meet the rising demand of commercial applications [13][14][15].…”