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The adsorption kinetics of thiophene on WS 2 nanoparticles with fullerene-like (onion-like) structure has been studied at ultra-high vacuum conditions by sample temperature ramping techniques. At low temperatures, thiophene adsorbs molecularly. The formation of H 2 S and alkanes is evident at greater temperatures on fully sulfided as well as reduced and oxidized WS 2 nanoparticles.

Presented are thermal desorption spectroscopy (TDS) data of alcohol adsorption on single-wall carbon nanotubes (CNTs) supported on silica. The adsorption kinetics of methanol, ethanol, propanol, 2-propanol, butanol, pentanol, and hexanol have been studied. Multimass TDS confirms molecular adsorption/desorption with low coverage binding energies, E 0 , increasing linearly with the number of carbons, n. The coverage, Θ, dependence of the heat of adsorption, E d (Θ), has been obtained by a Redhead analysis. The heat of sublimation increases linearly with n whereas the zeroth-order pre-exponential factor is approximately independent of n. In addition, TDS of alkanes (butane, pentane, hexane, trimethylpentane) as well as alcohol-alkane coadsorption data have been collected to characterize possible adsorption sites. Alkane TDS leads to fingerprint curves indicating three different adsorption sites (external, groove, internal) on CNTs, in agreement with earlier studies. For most of the alcohols only one monolayer TDS peak is seen indicating a dominance of lateral interactions. However, the coadsorption data provide evidence for alcohol adsorption on interior sites of the CNTs.

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JSC-1a (a simulated lunar dust sample) supported on a silica wafer (SiO 2 /Si(111)) has been characterized by scanning electron microscopy (SEM), energy dispersive x-ray (EDX) spectroscopy, and Auger electron spectroscopy (AES). The adsorption kinetics of water has been studied primarily by thermal desorption spectroscopy (TDS) and in addition by collecting isothermal adsorption transients. Blind experiments on the silica support have been performed as well. JSC-1a consists mostly of aluminosilicate glass and other minerals containing Fe, Na, Ca, and Mg, as characterized in detail in prior studies, for example, at NASA. The particle sizes span the range from a few micrometers up to 100 µm. At small exposures, H 2 O TDS is characterized by broad (100-450) K structures; at large exposures, distinct TDS peaks emerge, which are assigned to amorphous solid water (ASW) (145 K) and crystalline ice (CI) (165 K). Water dissociates on JSC-1a at small exposures but not on the bare silica support. Coadsorption TDS data (alkane-water mixtures) indicate that rather porous condensed ice layers form at large exposures, with the mineral particles acting most likely as nucleation sites. At thermal impact energies, the initial adsorption probability amounts to 0.92 ± 0.05. It is evident that the drop-and-dry technique, developed in studies about nanoparticles/tubes, can be extended to obtain samples for surface science studies based on powders consisting of particles with rather large diameters.