Adsorption of small hydrocarbons on rutile TiO2(110)

SURFACE SCIENCE

卷:650

Article

Dohnalek, Zdenek¹ 

[1] Pacific NW Natl Lab, Phys & Computat Sci Directorate, Richland, WA 99352 USA

关键词: Hydrocarbons;    Adsorption;    Desorption;    Temperature programmed desorption;    Sticking coefficient;   

DOI  :  10.1016/j.susc.2015.11.002

来源: Elsevier

【 摘 要 】

Temperature programmed desorption and molecular beam scattering were used to study the adsorption and desorption of small hydrocarbons (n-alkanes, 1-alkenes and 1-alkynes of C-1-C-4) on rutile TiO2(110). We show that the sticking coefficients for all the hydrocarbons are close to unity (>0.95) at an adsorption temperature of 60 K. The desorption energies for hydrocarbons of the same chain length increase from n-alkanes to 1-alkenes and to 1-alkynes. This trend is likely a consequence of additional dative bonding of the alkene and alkyne pi system to the coordinatively unsaturated Ti-5C sites. Similar to previous studies on the adsorption of n-alkanes on metal and metal oxide surfaces, we find that the desorption energies within each group (n-alkanes vs. 1-alkenes vs. 1-alkynes) from Ti-5C sites increase linearly with the chain length. The absolute saturation coverages of each hydrocarbon on Ti-5C, sites were also determined. The saturation coverage of CH4, is found to be similar to 2/3 monolayer (ML). The saturation coverages of C-2-C-4 hydrocarbons are found nearly independent of the chain length with values of similar to 1/2 ML for n-alkanes and 1-alkenes and 2/3 ML for 1-alkynes. This result is surprising considering their similar sizes. (C) 2015 Elsevier B.V. All rights reserved.

【 授权许可】

Free