Desorption energies of linear and cyclic alkanes on surfaces: anomalous scaling with length

Abstract

The desorption energies, DE against the polarizabilities, a, of the alkanes also reveals that DE cannot arise from the scaling of the polarizability with chain length. We discuss other possible origins of DE including lattice commensurability effects, temperature, and desorption order.

Reactivity screening of silica

“…The small decrease in E def with chain length would, however, be consistent with blocking of more defect sites and a smaller total surface density of longer chain alkanes. Repulsive lateral interactions (g/E 0 $ 20%) have been observed which reflect the influence of the support since for MgO attractive [4] and for Zn-ZnO [5] as well as Al 2 O 3 [3] repulsive interactions are present whereas for most metals [8] and graphite [7] the TDS peak positions are independent of the exposure indicating rather small effects of lateral interactions.…”

“…The heat of adsorption, E d , appears to scale linearly with chain length [7]. At low adsorption temperatures, condensation in bi-and multilayers leads to additional TDS features following 0th order kinetics.…”

“…Therefore, thermal desorption spectroscopy (TDS) studies characterizing the adsorption kinetics of alkanes have been conducted for a large variety of single crystal surfaces including graphite, [2] sapphire, [3] MgO, [4] ZnO, [5] Ru, [6] and Cu [7,8]. Furthermore, molecular beam scattering techniques have been applied to characterize the adsorption dynamics (i.e.…”

CO Adsorption on FeO x Nanoclusters Supported on HOPG—Effect of Oxide Formation on Catalytic Activity

“…Although a wealth of kinetic studies have been conducted on clean HOPG (see e.g., Refs. [18][19][20] we are only aware of a few molecular beam scattering projects [21][22][23][24][25]. In addition, still rather few molecular beam scattering studies have been conducted on supported model catalysts [26][27][28].…”

Adsorption of iso-/n-butane on an anatase thin film: a molecular beam scattering and TDS study

“…Therefore, kinetic parameters of alkane adsorption/desorption have been obtained by thermal desorption spectroscopy (TDS) for a large variety of single crystal surfaces including graphite [17], sapphire [18], ZnO [19], Pt [20], Ru [21], Cu [22,23], and C-/TiO 2 nanotubes [15]. Furthermore, molecular beam scattering techniques have been applied to characterize the adsorption dynamics (i.e.…”