Nanoparticles of MoS2 and WS2 were synthesized by decomposing the
appropriate metal hexacarbonyl in the presence of sulfur dissolved in decalin at 140°C.
A significant fraction of the nanoparticles was ≤ 15 nm in diameter as verified by
Transmission Electron Microscopy. The process was repeated in the presence of silica
and then titania to produce supported metal sulfides. The unsupported nanoparticles were
found to exhibit a size-dependent shift in their threshold UV-visible absorption due to
quantum confinement. Photocatalytic properties of each sulfide from synthesis in decalin
were explored by using each as a catalyst in the photodegradation of methylene blue by
visible light. These sulfides were also used to catalyze the photodegradation of acetone.
Unsupported MoS2 and WS2 nanoparticles catalyzed the photodegradation of
acetone under visible light of ≥ 400 nm wavelength. This is the first study reporting the
photocatalytic properties of the unsupported WS2 nanoparticles. Photodegradation of
methylene blue under ≥ 435 nm irradiation was detected using unsupported WS2 but not
unsupported MoS2, likely because activity was masked by the likely photobleaching of
the dye. When deposited on silica or titania, the nanosized MoS2 and WS2 could be
uniformly distributed in aqueous solutions to maximize the photocatalytic efficiency. Correcting the absorbance measurements for light scattering by solids proved to be beneficial for extracting kinetic information. Both silica deposited sulfides were found to significantly increase the rate of methylene blue photodegradation, and deposited WS2 increased this rate significantly more than deposited MoS2. Similarly, both titania deposited sulfides significantly increased the rate of methylene blue photodegradation, and the deposited WS2 increased this rate significantly more than the deposited MoS2 / Synthesis of the sulfide photocatalysts -- Characterization of synthesized nanoparticles -- Photocatalytic degradation tests : setup and protocols -- Photocatalytic degradation tests : results. / Department of Chemistry
| Identifer | oai:union.ndltd.org:BSU/oai:cardinalscholar.bsu.edu:123456789/193486 |
| Date | January 2009 |
| Creators | James, Derak J. |
| Contributors | Zubkov, Tykhon |
| Source Sets | Ball State University |
| Detected Language | English |
| Format | iv, 64, [1] p. : digital, PDF file, ill. (some col.). |
| Source | CardinalScholar 1.0 |
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