G′ band in double- and triple-walled carbon nanotubes: A Raman study

Double- and triple-walled carbon nanotubes are studied in detail by laser energy-dependent Raman spectroscopy in order to get a deeper understanding about the second-order G[superscript '] band Raman process, general nanotube properties, such as electronic and vibrational properties, and the growth method itself. In this work, the inner nanotubes from the double- and triple-walled carbon nanotubes are produced through the encapsulation of fullerene peapods with high-temperature thermal treatments. We find that the spectral features of the G[superscript '] band, such as the intensity, frequency, linewidth, and line shape are highly sensitive to the annealing temperature variations. We also discuss the triple-peak structure of the G[superscript '] band observed in an individual triple-walled carbon nanotube taken at several laser energies connecting its Raman spectra with that for the G[superscript '] band spectra obtained for bundled triple-walled carbon nanotubes.National Science Foundation (U.S.) (Grant 1004147

Photocatalytic Stability of Single- and Few-Layer MoS₂.

MoS2 crystals exhibit excellent catalytic properties and great potential for photocatalytic production of solar fuels such as hydrogen gas. In this regard, the photocatalytic stability of exfoliated single- and few-layer MoS2 immersed in water is investigated by μ-Raman spectroscopy. We find that while the basal plane of MoS2 can be treated as stable under photocatalytic conditions, the edge sites and presumably also defect sites are highly affected by a photoinduced corrosion process. The edge sites of MoS2 monolayers are significantly more resistant to photocatalytic degradation compared to MoS2 multilayer edge sites. The photostability of MoS2 edge sites depends on the photon energy with respect to the band gap in MoS2 and also on the presence of oxygen in the electrolyte. These findings are interpreted in the framework of an oxidation process converting MoS2 into MoOx in the presence of oxygen and photoinduced charge carriers. The high stability of the MoS2 basal plane under photocatalytic treatment under visible light irradiation of extreme light intensities on the order of P ≈ 10 mW/μm(2) substantiates MoS2's potential as photocatalyst for solar hydrogen production

Inorganic double helices in semiconducting SnIP

Color drawing of Hattiesburg, MS courthouse, featuring Confederate monument; probably produced as promotional material for the Illinois Central Railroad Company\u27s Panama Limited servicehttps://egrove.olemiss.edu/rayburn/1245/thumbnail.jp