This study is focused on the application of a highly-doped layered perovskite, La 2-Ti 2 O 7 , as the photocatalyst for the photocatalytic decomposition of isopropanol (IPA). The La 2 Ti 2 O 7 powder prepared by solid state reaction was characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), UV-Vis diffuse reflectance spectrophotometry (UV-DRS), X-ray photoelectron spectroscopy (XPS), and zeta potential. The temporal behavior of the photocatalytic decomposition of IPA in aqueous solution by the UV/La 2 Ti 2 O 7 , with a photoreactor operated in a recirculation mode, was studied under various conditions including solution pH, light intensity, and La 2 Ti 2 O 7 loading. The decomposition of IPA in aqueous solution by La 2 Ti 2 O 7 photocatalytic processes was found to be technically feasible. A kinetic equation was developed for modeling the photocatalytic decomposition of IPA by the UV/La 2 Ti 2 O 7 photocatalytic processes.

The adsorption and desorption of stilbene on Ag/Ge(111)-(√3 × √3)R30° (Ag/Ge(111)-√3) were investigated using low-energy electron diffraction (LEED), scanning tunneling microscopy (STM), temperature-programmed desorption (TPD), and density functional theory (DFT). Both trans- and cis-stilbenes form a (2 × 1) overlayer structure on Ag/Ge(111)-√3 at a coverage of ∼1 ML. The STM images show parallel strips with three equivalent directions, indicating a self-ordered molecular structure. At a coverage of less than 1 ML, the TPD of cis-stilbene shows only one peak, attributed to submonolayer desorption. The TPD peaks are indistinguishable for desorption of trans-stilbene from the surface submonolayer and multilayer. This is due to the simultaneous desorption and/or thinning of adsorbed multilayers during the TPD process, as determined from the STM analysis of adsorbed trans-stilbene structures before and after annealing. The TPD traces fit the half-order kinetics for molecular desorption of stilbene from Ag/Ge(111)-√3 with desorption energies of 20.1 (cis-) and 21.3 kcal/mol (trans-), which are comparable with the calculated values using the DFT method. A plausible explanation for the stilbene desorption process on Ag/Ge(111)-√3 is proposed and discussed.