Desorption Kinetics of Ar, Kr, Xe, N₂, O₂, CO, Methane, Ethane, and Propane from Graphene and Amorphous Solid Water Surfaces

Abstract

The desorption kinetics for Ar, Kr, Xe, N2, O2, CO, methane, ethane, and propane from graphene-covered Pt(111) and amorphous solid water (ASW) surfaces are investigated using temperature-programmed desorption (TPD). The TPD spectra for all of the adsorbates from graphene have well-resolved first, second, third, and multilayer desorption peaks. The alignment of the leading edges is consistent the zero-order desorption for all of the adsorbates. An Arrhenius analysis is used to obtain desorption energies and prefactors for desorption from graphene for all of the adsorbates. In contrast, the leading desorption edges for the adsorbates from ASW do not align (for coverages < 2 ML). The nonalignment of TPD leading edges suggests that there are multiple desorption binding sites on the ASW surface. Inversion analysis is used to obtain the coverage dependent desorption energies and prefactors for desorption from ASW for all of the adsorbates.

Surface heterogeneity and inhomogeneous broadening of vibrational line profiles

“…The distribution recovered is not dissimilar to those reported for CO and other small molecules on a number of heterogeneous surfaces. 19,25,26,278,29 Clearly, Figure 4 defines the range of interaction energies associated with the surface heterogeneity on the aSiO 2 surface. However, it also gives us the Name., 2012, 00, 1-3 This journal is © The Royal Society of Chemistry 20xx…”

“…In approaching this problem, we have utilised the P(E des ) versus E des data of Kay and co-workers. 29 Figure 6 shows the comparison of the experimental and simulated line shapes. It should be noted that the vibrational spectrum of sub-monolayer coverages of CO adsorbed on p-ASW at 20 K exhibits two strong features at 2139 and 2153 cm -1 , respectively.…”

A multi-technique study of CO2 adsorption on Fe3O4 magnetite

“…50 The chemical potential, and hence the vapour pressure and desorption rate, is defined by the two-phase coexistence, and as long as surface diffusion remains faster than desorption, the desorption rate is independent of coverage. 54 Moreover, the molecule-molecule interaction within the condensed phase must be strong compared to the moleculesubstrate interaction, as this ensures that evaporation from the condensed phase into the 2D gas is the rate determining step. In our case, the "condensed" phase is that observed at a coverage of four CO 2 molecules per (…”

“…35,54 Thus, additional CO 2 molecules are squeezed into the ordered structure. The noninteger number of molecules implies there is no one site in the unit cell where an additional CO 2 molecule gets accommodated, rather the incorporation must result in displacement of the already adsorbed CO 2 away from their favored position above the Fe cation.…”

Peeling the astronomical onion

“…Adsorption of CO then leads to cluster growth on graphite 52 and graphene surfaces while forming a monolayer on water surfaces. 53 CO is a precursor to the formation of many complex organic molecules (COMs). 2 Hydrogenation produces formaldehyde (H 2 CO) and methanol (CH 3 OH).…”