Synthesis, Characterization and Visible-Light Photocatalytic Activity of Solid and TiO2-Supported Uranium Oxycompounds

Abstract

In this study, various solid uranium oxycompounds and TiO2-supported materials based on nanocrystalline anatase TiO2 are synthesized using uranyl nitrate hexahydrate as a precursor. All uranium-contained samples are characterized using N2 adsorption, XRD, UV–vis, Raman, TEM, XPS and tested in the oxidation of a volatile organic compound under visible light of the blue region to find correlations between their physicochemical characteristics and photocatalytic activity. Both uranium oxycompounds and TiO2-supported materials are photocatalytically active and are able to completely oxidize gaseous organic compounds under visible light. If compared to the commercial visible-light TiO2 KRONOS® vlp 7000 photocatalyst used as a benchmark, solid uranium oxycompounds exhibit lower or comparable photocatalytic activity under blue light. At the same time, uranium compounds contained uranyl ion with a uranium charge state of 6+, exhibiting much higher activity than other compounds with a lower charge state of uranium. Immobilization of uranyl ions on the surface of nanocrystalline anatase TiO2 allows for substantial increase in visible-light activity. The photonic efficiency of reaction over uranyl-grafted TiO2, 12.2%, is 17 times higher than the efficiency for commercial vlp 7000 photocatalyst. Uranyl-grafted TiO2 has the potential as a visible-light photocatalyst for special areas of application where there is no strict control for use of uranium compounds (e.g., in spaceships or submarines).

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

“…The synthesized and reference photocatalysts were tested in the oxidation of acetone vapor in a continuous-flow setup designed for the evaluation of steady-state oxidation rates and stability of photocatalytic performance. The details on the experimental setup and evaluation of photocatalytic activity can be found in our previously published paper [ 50 ]. Highly powerful UV (λ max = 371 nm) and blue (λ max = 450 nm) LEDs were used for the irradiation of photocatalysts and evaluation of their activity in the UV and visible regions, respectively.…”

“…The setup had a special valve system for the alternate analysis of the inlet and outlet reaction mixtures using an FTIR spectrometer FT-801 (Simex LLC, Novosibirsk, Russia) equipped with an IR long-path gas cell (Infrared Analysis Inc., Anaheim, CA, USA). The quantitative analysis of acetone and CO 2 was performed using the Beer–Lambert law by the integration of collected IR spectra in corresponding regions [ 50 ]. Figure S1c in the Supplementary Materials shows a typical CO 2 concentration profile during the photocatalytic experiment.…”

Efficient Removal of Cr(VI) by TiO2 Based Micro-Nano Reactor via the Synergy of Adsorption and Photocatalysis

“…TiO 2 , as a commonly used photocatalyst, has been widely used in the pollutant treatment field [17][18][19]. However, TiO 2 suffers from the limitation of its relatively large bandgap (approximately 3.2 eV for anatase and 3.0 eV for rutile) and low quantum efficiency due to the quick recombination of photo-induced electrons and holes [20,21]. Therefore, enhancing the photoexcitation and separation efficiency of photo-induced electron-hole pairs is important for industrial applications [22,23].…”

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

“…The schematic diagram of this setup and details on the operation process can be found in Supplementary (Figure S1) . Validation of the setup was previously performed during the investigation of functional properties of various photocatalytic systems [ 43 , 44 , 45 , 46 ]. The rate of air flow was 67 ± 1 mL min −1 and the inlet concentration of acetone vapor was ca.…”