A. Gutiérrez-Sosa

Probing molecular orientation in corrosion inhibition via a NEXAFS study of benzotriazole and related molecules on Cu(100)

Abstract The orientation of benzotriazole on Cu(100) has been studied using near-edge X-ray absorption fine structure (NEXAFS) at the C and N K-edges. At submonolayer coverage, benzotriazole (C6H5N3) is found to adsorb with the molecular plane close to perpendicular to the Cu(100) surface, as indicated by the polarization dependence of the π∗ features. The orientation of benzimidazole (C7H6N2) and 1-methyl benzotriazole (C7H7N3) on Cu(100) have also been studied, and are found not to be oriented at submonolayer coverage. This, along with the orientation at multilayer coverage suggests a specific first-bonding-layer origin for the corrosion inhibitor properties of benzotriazole.

Influence of Cu overlayers on the interaction of CO and CO2 with ZnO(000text-decoration:overline1)-O

NEXAFS and FT-RAIRS have been used to investigate the adsorption of CO and CO2 on ZnO(000text-decoration:overline1)-O and its modification by copper overlayers. NEXAFS data indicate a CO32– species with the molecular plane within 30° of the surface normal following CO and CO2 adsorption on the clean surface at 130 K. Upon low-temperature deposition of a submonolayer Cu film, CO32– species were no longer formed following CO adsorption, although molecular CO was evidenced with the molecular axis within 20° of the surface normal. A single ν(CO) band observed in FT-RAIRS indicates that the CO is adsorbed on 2D Cu(110)-like sites in an atop position. Preannealing the Cu film to 400 K led to a redistribution of Cu into 3D islands, as evidenced by FT-RAIRS. Exposure to CO of such a surface at 130 K resulted in both CO and CO32– formation. This suggests that Cu initially nucleates at the active sites for CO32– formation on ZnO(000text-decoration:overline1)-O which are uncovered during the onset of 3D island growth.

Carbonate co-adsorption geometry on TiO2(110)1×1-Na

Abstract The influence of Na on the adsorption and reaction of CO2 with TiO2(110)1×1 has been studied using C K-edge NEXAFS. CO2 forms carbonate on the Na-covered surface, the molecular plane being twisted 32±5° out of the [001] azimuth with a tilt of 46±5° away from the surface normal.