Adsorption of Acetic Acid on Rutile TiO2(110) vs (011)-2 x 1 Surfaces

作者：Tao Junguang; Luttrell Tim; Bylsma Jason; Batzill Matthias^*

来源：Journal of Physical Chemistry C, 2011, 115(8): 3434-3442.

DOI：10.1021/jp111270x

Acetic acid adsorption on the rutile TiO2(110) and (011)-2 x 1 surfaces is compared by temperature-programmed desorption, ultraviolet photoemission spectroscopy, and scanning tunneling microscopy. In contrast to the well-established bidentate adsorption of carboxylic acids on the (110) surface, we find a monodentate adsorption on the (oil)2 x 1 surface as the most likely adsorption geometry. The adsorption dynamics is also very different for the two surfaces. While acetic acid adsorbs homogeneously on the (110) surface, acetic acid adsorbs as quasi-one-dimensional dusters on the (oil)2 x 1 surface. Initially, acetate adsorbs only at surface defects, but subsequent acetic acid can adsorb along these nucleated acetate dusters and spread to the defect-free terraces. Therefore, the preadsorbed acetic acid facilitates further acetic acid adsorption in a self-catalyzed adsorption mechanism. The acetic acid clusters preferentially grow along the [0 (1) over bar1] crystallographic surface direction forming up to tens of nanometers long dusters with a usual width of three acetates. In TPD studies acetate reacts in a unimolecular dehydration reaction yielding ketene as the main desorption product at similar to 585 K for both surfaces.

• 出版日期2011-3-3